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Management of the Falkland Islands Loligo gahi fishery is by a combination of effort control and in-season assessment of the state of the stock in relation to biological reference points. There are two fishing seasons, from February to May and from August to October inclusive. There appear to be at least two, and sometimes three cohorts that recruit to the fishery over a year, in January, April/May and October. The fishing seasons therefore do not directly coincide with the separate cohorts; the second cohort is caught in both the first and second seasons. Assessments of the cohorts were made using a Delury depletion model. In situations when a Delury could not be fitted satisfactorily, an extension was developed in which annual trends in catchability coefficients were used together with individual vessel CPUE data to estimate stock size. The Delury and its extension enabled both first and second cohorts to be assessed for all years from 1987 to 1996. Results indicated that the cohorts have different dynamics and should be considered as separate stocks. Both cohorts have been declining in size over the last several years. The significance of a transition between two distinct stocks in a single fishing season is discussed in the context of real-time management of this fishery.

The electrophysiology of extraocular photoreception in the myopsid squid, Loligo forbesi Steenstrup 1856 has been examined. Extracellular generator potentials were evoked by white light flashes. Intracellular recordings from extraocular photoreceptor cells in the parolfactory bodies of the squid demonstrated that they had resting potentials around -40 mV, and were depolarised by flashes of white, but not red light (>650 nm). The evoked depolarisation consisted of a transient component, followed by a steady plateau component. The amplitude of depolarisatio n increased with the logarithm of the light intensity and was maintained for the duration of the light stimulus. Action potentials were seen in some recordings and these increased in frequency during light flash stimulation.

Length-frequency data on squid (Loligo forbesi) collected during trawling surveys in Scottish waters from 1980 to 1994 were analysed to describe temporal and spatial patterns in abundance and to examine the prospects for using survey abundance to forecast fishery abundance. Loligo was patchily distributed in space and time. Distribution patterns in the North Sea in February appeared to be strongly related to bottom temperature (squid avoided waters

Over 2000 individuals of Lolliguncula brevis were collected from 1975 to 1979 in the northern Gulf of Mexico off the Texas coast; their growth and reproductive biology were analyzed by traditional fisheries methods (ELEFAN analysis of the length-frequency data). From 1994 to 1996, 112 squid were captured in Galveston Bay, near Galveston Island, Texas, and their age and growth determined by statolith increment analysis. The results were strikingly different between the two approaches. Length-frequency analysis of growth overestimated life span by a factor of three to seven times. Statolith increment counts, verified by laboratory growth validation experiments, indicate that this species is very short-lived, in the order of 100-200 days depending on temperature. A slight increase in temperature during the early stage of development can greatly shorten the life span. This study provides evidence that increased temperature during a squid's early growth period could markedly accelerate growth. Mature individuals occurred throughout the year, although there were many more mature males collected than females. Gonad growth and maturation in L. brevis appear to be associated more with size than with individual age. There is now compelling evidence that length-frequency analysis should be abandoned as a technique for determining squid growth.

The skin ofLoligo vulgarisandIllex illecebrosuscontains a thick layer of amorphous material. InLoligoit lies above and inIllexbelow the chromatophore layer. We can find no mention of this layer in the considerable literature on squid skins despite its potential importance as a protection to underlying tissues and as a possible barrier to cutaneous oxygen uptake.Cephalopods have soft complicated skins. Embedded in the skin, most species have chromatophores, small bags of pigment that can be expanded by muscles that are under direct nervous control from the brain. There is an extensive literature on the physiology of chromatophores (Packard, 1988) and on their function in the behaviour of the animals (Hanlon & Messenger, 1996; Packard & Hochberg, 1977). Further cutaneous structures concerned in the determination of the colour of living cephalopods, the reflecting iridophores and leucophores (Cloney & Brocco, 1983), and the light generating photophores (Herring, 1988), have been the subject of a number of reports but other skin features such as the distribution of blood vessels have attracted little attention.

This study constitutes a first approach of the use of a stereological method for estimating potential fecundity in cephalopods. Squid samples were taken in two regions from the south coast of Portugal. In Olhäo, commercial trawlers provided mainly immature squid during winter. In Quarteira, a summertime traditional jigg fishery provided maturing and mature squid, which were used in the fecundity estimates. A total of 38 female squid, Loligo vulgaris (Cephalopoda: Loliginidae), from all maturity stages were analysed. The results revealed that: (1) the development of the ovaries is monocyclic and the oocyte growth and development is asynchronous; (2) oogenesis proceeds in six histological stages, showing statistically different oocyte maximum diameters; and (3) the best estimate of potential fecundity seems to be obtained by counting all oocytes in the ovaries of the mature females in maturity stage IV

Trace elements in squid statoliths were analyzed by PIXE for the following fourteen species in five families of different habitat origin: Ommastrephidae, Ommastrephes bartrami, Dosidicus gigas, Sthenoteuthis oualaniensis; Gonatidae, Gonatopsis makko, G. borealis, Berryteuthis magister; Loliginidae, Loligo bleekeri, L. duvaucelii, L. chinensis, L. edulis and Sepioteuthis lessoniana; Sepiidae, Sepia aculeata and Sepiella inermis; Sepiolidae, Rossia pacifica, Manganese, iron, copper, zinc and strontium were detected from statoliths of all species examined. Among these trace elements, Sr is the highest in concentration. Variation of statoliths Sr concentration reflects taxonomic position and the habitat of specimens. In Ommastrephids and Gonatids, that have oceanic habitat, statoliths Sr concentration is relatively high whereas that of Loliginids and Sepiids, that have coastal habitat, is comparatively low. This fact supports our previous report on this subject. R. pacifica exceptionally shows high statoliths Sr concentration although this species inhabits in coastal water.

In the present paper the species from the genus Lolliguncula Steentrup, 1881 (Cephalopoda: Loliginidae) in Southeastern Pacific Ocean are reviewed. The presence of Lolliguncula (Lolliguncula) panamensis Berry, 1911, Lolliguncula (Loliolopsis) diomedeae Hoyle, 1911 and Lolliguncula (Lolliguncula) argus Brakoniecki and Roper, 1985 are confirmed from Mexican waters to Peru and the species Lolliguncula (Lolliguncula) argus collected during a cruise of the R/V Anton Bruun from 1966 off the coast of South America is recorded for the first time in Peruvian waters. A key to identification of Pacific species is given. We report a diagnostic feature with taxonomic remarks of these species. Updated information on the distribution, biology, and fisheries of each species also is discussed.

Seven specimens of Lolliguncula (Lolliguncula) argus, were collected in the shrimp fisheries of the Gulf of California and five specimens from the western coast of Baja California Peninsula, deposited in the Santa Barbara Museum of Natural History (USA), are examined and reported. These records expand species geographic distribution range for approximately 950 km and report the maximum size of mantle length 38.8 mm for males and 60.8 mm for females. Morphometric data of the 12 collected specimens are presented, and species funnel organ and statoliths are described.

In this volume we have considered the problems of investigation special to cephalopods. Almost all our knowledge of their general biology is restricted to the shelf-living, muscular, negatively buoyant (the Loliginidae and Octopodidae) or gas-supported species (the Sepiidae and Nautilidae) and members of the Ommastrephidae which move on to the continental shelves at certain seasons. These species of the continental shelves comprise only about 15% of all cephalopod genera and live in water of less than 300 m depth, which covers only 6% of the Earth’s surface. They do not represent the majority of cephalopod species or much of their total biomass; 85 % of genera are spread in the upper 2000 m and across the bottom of the deep oceans, which occupy 66 % of the Earth’s surface. Over 40% of these genera are neutrally buoyant by oil or chemical means and may have very different lifestyles from the forms we know from shallow water. Improvement of our knowledge of the ecology of deep water forms is hindered by our poor direct sampling methods and rests largely upon sampling from stomachs or regurgitations of the predators that eat cephalopods.

For 31 of the 33 extant species of pinnipeds it is either known or suspected that they include cephalopods in their diet. The two exceptions are the Baikal Seal and the Caspian Seal, which inhabit freshwater where cephalopods do not occur. The available evidence indicates that no species of seal specializes entirely on cephalopods and only few regularly eat appreciable quantities of this prey, although for several they appear to be seasonally important prey. For most pinnipeds only rudimentary prey identifications have been published. The most common taxa of cephalopods reported to be consumed by seals are members of the neritic Loliginidae, the oceanic Ommastrephidae, Onychoteuthidae and Gonatidae, as well as benthic octopods. Too few quantitative diet analyses on enough pinnipeds have been done to quantify the consumption of cephalopods by seals globally with any precision.

Over 80 % of odontocete species and two balaen whale species include cephalopods in their diet regularly. In 28 odontocetes they comprise the main food. Predominently cephalopod-eating species are found in the Physeteridae, Ziphiidae, Phocaenidae and Delphinidae. By far the most important of the 28 families of cephalopods represented in the diet of cetaceans are the oceanic Ommastrephidae, Histioteuthidae and the Cranchiidae, with the neritic Loliginidae assuming most importance on the continental shelves. Onychoteuthidae and Gonatidae assume greater importance in polar regions and the North Pacific. The other 22 families form a reservoir from which various cetaceans eat opportunistically and as their sizes permit. There are probably less than 60 cephalopod species regularly in the diet of cetaceans. Species composition of the food varies regionally, seasonally and annually. Locally, the greatest difference is found between cetaceans that live in oceanic water and continental shelf water. There is a positive correlation between the size of the prey and both the size of pelagic feeding cetacean species and the growth stage within a species. This leads to some partitioning of the food and less competition. Broad estimates show that the biomass of oceanic cephalopods consumed annually by the largest odontocete, Physeter catodon , may be over twice the biomass of fish caught by man. Regional estimates show that consumption by cetaceans of little known cephalopod species may greatly exceed the local catches of commercial fish.

Preliminary estimates of trawl codend selectivities for the European long-fin squid, Loligo forbesi (Cephalopoda: Loliginidae), were made following analyses of catch data obtained during annual fishing surveys of Faroese and Scottish waters involving three research vessels (1977-1993). For the standard survey, the trawl was fitted with a 75 mm diamond mesh codend. The estimated mean selection (mantle) lengths (L 50 ) for this species were 14.6, 13.9, and 14.9 cm, respectively.

Confusion abounds regarding the relative generic status of many member species of the squid family Loliginidae. A taxonomie reorganisation within the family has been proposed in whichLoligo species from the Indo-Pacific possessing photophores on the ink sac, includingLogligo edulis andLoligo chinensis, are removed to the newly created genusPhotololigo. This system of classification has not however gained general acceptance, and some authors have continued to refer to these species asLoligo. Here biochemical genetic data gathered using allozyme electrophoresis are presented supporting the assertion thatL. edulis andL. chinensis should indeed be positioned in a genus distinct from that characterised by the type speciesLoligo vulgaris vulgaris. Cluster analysis of allele frequency data from 22 putative enzyme-coding loci suggests thatL. edulis andL. chinensis are as genetically distant fromL. vulgaris vulgaris as are members of the confamilial generaAlloteuthis, Uroteuthis andSepioteuthis, and as such warrant separate generic status. We conclude that the genusPhotololigo is valid.

Due to study the food regime of Arius dussumieri, a total of 132 specimens were collected from Oman sea waters, Sistine & Baluchistan province. The stomach content, were taken into consideration and it was found that the amount of full, semi-full and empty stomachs were 31, 33 and 36 percent, respectively; of which the highest frequency was in winter (74%) and the lowest was in summer (24%). On the other hand, the fullness index was studied with the highest and lowest value for spring (44%) and winter (5%), respectively. The GaSI shows that A. dussumieri, has better feeding in spring and summer but feeding (up in male) was decreased in autumn and winter. The Food Preference (FP) Index was estimated as: Fishes (39%), Crustacean (40%) and Molluscs (20%) namely all of them are considered as minor food in all four seasons. The most important food items were identification as fishes: Carangidae, Engraulidae & Leiognathidae; crabs: Portunidae & Porcellanidae; shrimp: Alpheidae; cephalopods: Loliginidae & Opisthoteuthidae; gastropods: Muricidae & Naticidae.

This first description of behavioural interactions between benthic pyjama sharks Poroderma africanum (Chondrichthyes: Scyliorhinidae) and spawning squids Loligo vulgaris reynaudii (Cephalopoda: Loliginidae) was made from underwater video recordings. The behaviours are described and illustrated to show that the sharks searched for squids in egg beds, then rested there partially hidden and immobile. The pyjama sharks at-tempted to ambush the squids when they approached to lay their eggs after they had apparently habituated to the predators. Although normally nocturnal, the pyjama sharks had emerged by day from caves and cracks in the rocky reef to attack the spawning squids, thereby benefiting from an occasionally available resource.

The reproductive strategies of male and female Loligo forbesi Steenstrup, 1856 were investigated from samples obtained from commercial catches and research cruises in Irish waters. In females maturity increased with size, but in males two modes in the size at maturity were identified, with approximately 40% mature at small size (180–200 mm mantle length), and the remainder mature at >250 mm mantle length. The difference in estimated age of the two modes of mature males was small, so size differences were probably due to different growth rates. Growth and maturation proceeded together in both sexes over much of the life-cycle. The effect of maturation on relative growth of somatic tissues was examined using analysis of covariance and multivariate regressions. In males there was a significant decline in total mass, and in mass of mantle, head and viscera, relative to mantle length with maturation. In females total mass was not significantly affected by maturation, but relative masses of head, mantle and viscera declined with maturation, indicating that energy was diverted from somatic growth to gonad production. Potential fecundity estimates were obtained by counting eggs and ova in the oviduct and ovary of mature females and were in the range 2500 to 10,500 (mean 5800). Fecundity was positively related to mantle length. The ovaries of mature females contained a range of egg sizes and developmental stages, indicating that spawning probably occurs intermittently.

Samples of the squid Loligo forbesi Steenstrup 1856 were obtained from commercial catches and research cruises in the Irish and Celtic Seas from August 1991 until October 1993. Age and growth of L. forbesi were estimated from putative daily statolith growth increment counts and from length-frequency data. Indirect evidence of the daily deposition of growth increments was obtained by counting increments on statoliths from immature female squid from successive monthly modes, during a four-month period when length-frequency growth estimates were high. Female growth estimates from length-frequency analysis (15–30 mm per month) were slightly lower than statolith-based estimates (30 mm per month). Statolith data indicated that both sexes had a life-span of approximately one year and that males grew faster and attained a larger size than females. In both sexes growth was found to be logarithmic over the size range sampled (28–505 mm mantle length). Mean estimated age of mature males and females was 317 and 312 days respectively, with the minimum age at maturity found to be 236 and 241 days. Back-calculations of hatching dates showed an extended spawning season from November to May. Squid hatched in the spring grew faster than those hatched in the autumn and winter. In post-recruit L. forbesi, growth of head, mantle and viscera were approximately isometric with body mass. The digestive gland showed slight positive allometry, whilst reproductive organs showed strong positive allometry.

Age, growth and maturation of Loligo vulgaris were studied by examination of growth increments within statoliths of 294 specimens (mantle length, ML, ranging from 31 to 498 mm) caught on the west Saharan shelf between 1985 and 1988. Maximum age was 335 d (290 mm ML) for females, and 396 d (498 mm ML) for males. Growth rates varied considerably among individuals with a greater range in males. Sexual dimorphism in length was apparent after about 210 d. Males and females diverged considerably in weight, with males reaching a greater weight after about 180 d. Growth in length between 124 and 396 d was best described by a power function, while growth in weight was best described by the Gompertz function. Males started maturing at 180–210 d and mature males ranged in age between 250 and 396 d; while females started maturing at 240–270 d and mature females ranged between 285 and 335 d. Loligo vulgaris hatched throughout the year with two distinct peaks; in winter (December - early March) and summer (June-July). The life cycle of L. vulgaris populations on the west Saharan shelf lasts ~1 y, with large males (>450 mm ML) living slightly longer.

Horizontal starch gel electrophoresis was employed to investigate levels of genetic differentiation between 13 samples of the neritic squid species Loligo forbesi Steenstrup obtained from throughout the majority of its known geographical range. Six enzyme loci identified in a preliminary study as being polymorphic were screened for variation between samples. No significant differences in allele distribution were detected between any of the samples obtained from the Faroe Bank in the north to Lisbon in the south, suggesting that squid throughout this range in the vicinity of the continental shelf are able to maintain panmixia, and effectively belong to a single population sharing a common gene pool. No clinal variation in allele distribution was detected throughout this range, a result which complements the findings of a detailed morphological companion study of the same individuals. Comparison of this homogenous European continental shelf population with squid from the Azores revealed highly significant (P

A number of reproductive indices were compared with a subjective maturity scale for assessment of Loligo forbesi maturity. The ratio between nidamental gland length and mantle length corresponded well with female maturation, as did the ovary mass-soma mass and nidamental gland mass-soma mass ratios. For males, the ratio between spermatophoric complex mass and somatic mass was found to be the most suitable for maturity assessment. The timing of recruitment and maturation of L. forbesi in Irish waters was described from the size and maturity of squid in commercial landings in the south of Ireland during the years 1991–1993. Immature squid first appeared in commercial catches in July and August, and this represented the main period of recruitment. A second period of recruitment was apparent in December 1991, but was not identified in the 1992–1993 season. Mature females were present in the commercially exploited population between November and April, with a small number also found in the summer. The abundance of egg masses was used to indicate timing of spawning. Egg masses recovered from the Cork coast indicated that peak spawning occurred during the winter months, but continued on a small scale for much of the year.

Body size at sexual maturity, egg-size distributions, and potential reproductive output have been estimated for female and male squid, Loligo forbesi Steenstrup, off the west coast of Scotland. Two size modes at maturity were found in both sexes, but separation into size cohorts was more pronounced in males (180 and 350 mm mantle length, ML). Preliminary ageing studies based on statolith ring-counts suggest that these size modes are not due to different age groups at breeding. Females have a single size mode of mature eggs in the proximal oviduct, but may have at least two size modes of eggs within the ovary. This finding is interpreted as evidence of batch-spawning in this squid. There was a weak relationship between total egg numbers (range 1000 to 16000) and body size (range 196 to 318 mm ML) and between mature egg size and body size. Males showed a strong positive relationship between spermatophore length and body length but a weak relationship between total number of spermatophores and body size. The results are discussed in the context of flexibility of breeding strategies in the loliginids and variety of life-cycle patterns.

Two new species of dicyemid parasites from Dicyema are described from 2 species of Australian cephalopods, i.e., Dicyema calamaroceum n. sp. from Sepioteuthis australis Quoy and Gaimard, 1832 (southern calamary) collected from Spencer Gulf (SG) and Gulf St Vincent (GSV), South Australia (SA), Australia, and Dicyema pyjamaceum n. sp. from Sepioloidea lineolata Quoy and Gaimard, 1832 (striped pyjama squid), collected from SG, SA, Australia. Dicyema calamaroceum is a medium sized species that reaches approximately 2,400 μm in length. The vermiform stages are characterized by having 31-34 peripheral cells, a conical calotte, and an axial cell that extends to the propolar cells. An anterior abortive axial cell is absent in vermiform embryos, and verruciform cells were not observed in nematogens and rhombogens. Infusoriform embryos consist of 39 cells; 2 nuclei are present in each urn cell, and the refringent bodies are solid. Dicyema pyjamaceum is smaller than D. calamaroceum, with a body length that reaches approximately 1,950 μm. The vermiform stages are characterized by having 20-23 peripheral cells, a cap-shaped calotte that forms a cephalic swelling together with the parapolar cells, and an axial cell that extends to the propolar cells. An anterior abortive axial cell is absent in vermiform embryos. Verruciform cells and granules in propolar cells were observed in nematogens and rhombogens. Infusoriform embryos consist of 37 cells; 2 nuclei are present in each urn cell, and the refringent bodies are solid. This represents the first description of dicyemid parasites from Australia.

"Se analizo la abundancia y la distribucion del calamar dedal (Lolliguncula panamensis) capturado en 15 cruceros de pesca exploratoria en el golfo de California, durante 2003–2006 y 2008. Se registraron 66 lances positivos de calamar, en los que se capturo un total de 2460 individuos. Con base en el patron estacional de la temperatura superficial del mar, los individuos capturados se agruparon en dos periodos: frio (

The reproductive biology of the Panama brief squid was evaluated using reproductive indicators, and histological and histochemical analyses. A total of 2,460 squid were analyzed, which were captured during 15 exploratory fishing surveys in the Gulf of California during 2003 to 2006 and 2008. Of the total sample, 61% were female, 15% were male, and the rest were undifferentiated. Based on the frequency of the gonad developmental stages, the largest number of mature females was identified in February and October, whereas mature males were found in April and August. This result coincided with the gonadosomatic index. According to the histological analyses, we characterized 4 stages of oogenesis: previtellogenesis, vitellogenesis, postvitellogenesiswith mature oocytes, and postspawning. We also characterized 6 substages of oocyte and 2 structural indicators of spawning: oogonia (Po0), previtellogenic oocyte primary (Po1), previtellogenic oocyte secondary (Po2), vitellogenic primary oocyte (Vo1), secondary vitellogenic oocyte (Vo2), postvitellogenic oocyte (Pvo), postovulatory follicles, and atresia. Oocyte size among types showed significant differences (P < 0.05). The presence of postovulatory follicles, and oocytes of different sizes and various developmental stages throughout the study period indicates that the Panama brief squid has a synchronous ovarian development with multiple spawning. The size at first maturity (L50) indicates that males (mantle length, 51 mm) mature at lengths shorter than females (mantle length, 85 mm).

The population biology of the loliginid squid Loligo forbesi is described from monthly samples taken from the Scottish fishery (1990–1992). Length-frequency distributions are complex, particularly in males, with several size modes present in each month. Growth rates appear to be variable, with no single equation describing the growth of all putative microcohorts. Length-weight relationships vary in relation to maturity stage, and a decrease in size-adjusted mantle weight in later maturity stages indicates the diversion of resources from somatic to reproductive growth. The sex ratio among recruits is biased towards males but becomes increasingly biased towards females as the animals mature. There is an extended breeding season, from January to May with a peak in February–March, and two pulses of recruitment, in April and in July–September. Results are broadly consistent with the previously established view of this species as having a 1 year life-cycle. There is limited evidence for the existence of a separate offshore population, breeding earlier than the main coastal population and with wide interannual fluctuations in abundance. However, improved information on distribution is required to test this hypothesis.

27 páginas, 11 figuras, 7 tablas, The population biology of Loligo vulgaris and Loligo forbesi in Galician waters is described based on monthly samples from the fishery obtained during the period February 199 l-June 1992. Maturity was assessed using a maturity scale and indices. The estimated number of oocytes in mature females varied from 782 to 21 885 in L. vulgaris and from 1317 to 14 956 in L. forbesi, and showed a slight positive correlation with the length of the mantle (ML) for both species. Oocytes in the ovaries fall into three discrete size classes, which suggests that L. vulgaris and L.forbesi are intermittent or multiple spawning species. In L. vulgaris males mature at two different modal sizes, hence perhaps at two different ages, while in L. forbesi this occurs in both males and females. Males mature earlier in the season than females in both species. The maximum number of spermatophores found was 1010 and 1000 in two L. vulgaris males with 119 mm and 400 mm ML respectively, and 1035 in a L. forbesi male with 150 mm ML. In both species, spermatophore length increases with ML. Loligo forbesi males maturing at a larger size produce fewer but larger spermatophores than those maturing at a small size. Loligo vulgaris spawn throughout the year, but the period of more intensive spawning extends from December to April. The breeding season ofL. forbesi extends from December to May, the more intensive spawning extending from December to February. Sex ratios were variable for both species. Age and growth for both species and sexes were estimated by examining growth increments in the statoliths. Like-sized individuals had different ages in both species. The life span of L. vulgaris was estimated at about l year while L. forbesi seems to reach an age of 15-16 months. A list of prey species found in gastric contents of both species is given. The diet of L. vulgaris comprises fish (86.8%), cephalopods (6.0%), crustaceans (3.0%) and polychaetes (1.8%), and the diet of L. forbesi includes fish (75.6%), crustaceans (18.5%) and cephalopods (4.4%)., This work was funded by the Commission of the European Communities within the frame of this EEC research programme in the fisheries sector (FAR, contract no. MA 1.146).

Periodic increments within the squid statolith microstructure are now routinely used to obtain individual age estimates. Validation and culture studies have shown that statolith increments (similar to increments in larval fish otoliths) are produced daily in a number of squid species and in one sepioid. However, sample sizes for validation studies are small and there is need for further, more comprehensive validation experiments. Statolith age analysis has revealed that temperate squids can complete their life cycle in less than 2 yr while tropical species live for less than 8 mo. Obtaining individual age estimates has also facilitated the identification of cohorts by analysing hatch date distributions. Size-at-age analysis has been used for some preliminiary growth modelling, and there is a continued need for more accurate age-based squid growth models. There is now potential to use image analysis systems for increment counts and for width analysis of increments. Future studies should be aimed at obtaining age information from a wider number of species, considering how other features within the statolith microstructure, such as zones, might reflect past habitats, and determining how statolith length or weight measurements might be related to past growth histories.

The stomach contents of 723 Loligo vulgaris and 440 Loligo forbesi caught in the northwestern Spanish Atlantic waters have been examined. The diets of both species are described and compared. Loligo vulgaris shows 28 different types of prey belonging to four groups (Teleostei, Crustacea, Cephalopoda and Polychaeta) and Loligo forbesi 27 different types of prey belonging to three groups (Teleostei, Crustacea and Cephalopoda). Both species catch similar prey species but in different proportions. Cannibalism was observed in both species. Estimated prey sizes were smaller than squid sizes. No differences in feeding habits of males and females of both species were observed, but females seem to increase food intake during maturation. No significant changes were found in the diet of Loligo vulgaris within the size (DML) range studied (65–465 mm). Importance of cephalopods increased and importance of fish decreased in the diet of Loligo forbesi with growth (65–685 mm). Diet and food intake varied with se...

Stomach contents of Loligo forbesi obtained from commercial landings and research cruises in Irish waters and the Irish Sea were examined. A total of 62.3% of stomachs were empty. Fish remains occurred in 73.7% of all full or partially full stomachs, with crustaceans and cephalopods occurring in 26.4% and 7.5% respectively, L. forbesi was found to consume a wide range of fish and crustacean prey. Sagittal otoliths were used to identify fish species, and vertebrate to identify families. The most frequent species by per cent occurrence sprat (Sprattus sprattus), poor cod (Trisopterus minutus), Norway pout (T. esmarkii), and transparent goby (Aphia minuta). Crustaceans were the main prey item is squid of less than 100 mm mantle length, together with small clupeids and gobies. the predominant prey of medium-sized squid (100–220 mm) was found to be gadoid and clupeid fish, while gadoids and other cephalopods were the main prey of larger squid (>220 mm). Seasonal differences in the diet were apparent but were shown to be influenced by seasonal changes in squid size.

A large, discrete aggregation of squid was sampled at short intervals by means of jigging, midwater trawling and purse-seining. Differences among basic biological parameters of the population (e.g. length frequency) indicate that jigging is a more selective, and therefore biased, method of sampling than midwater trawling or purse-seining. This has important consequences for stock assessments that take commercial catches into account. The selectivity curve indicates that squid of mantle lengths (ML) 28–33 cm are over-represented (in terms of the situation in the population) in fisheries conducted by jigging and that squid 34 cm ML are under-represented if purse-seine results are considered to be representative of the population.

Cephalopod remains from the stomachs of four pilot whales Globicephala melaena (Traill, 1809), two bottlenose whales Hyperoodon planifrons Flower, 1882 and eight Commerson's dolphins Cephalorhynchus commersonii (Lacepede, 1804) stranded in Tierra del Fuego, Argentina were identified and measured. A total of 3365 lower beaks (mandibles) were identified and measured and from the rostral, crest and hood length, total wet and dry mass, mean mass and mean mantle length for each taxon were estimated. Over 68% of the cephalopods eaten by the pilot whales and all cephalopods eaten by the bottlenose whales were oceanic squid species (oegopsids). The Commerson's dolphins had only eaten shelf species of the families Loliginidae (97.5%) and Octopodinae (2.5%). Sixteen cephalopod families comprising 23 species were represented. In samples from Globicephala melaena, Loligo gahi represented 31% by number and 7.1% by estimated dry mass, Histioteuthis eltaninae, 29% by number and 4.9% by dry mass and the onychoteuthid Moroteuthis ingens 17.2% by number and 51.5% by dry mass. In samples from Hyperoodon planifrons, Histioteuthis eltaninae represented 24.0% of cephalopods by number but only 5.2% by dry mass, Taonius pavo 53% by number but only 2.5% by dry mass and the large onychoteuthid Kondakovia longimana only 2.5% by number but 65.8% by dry mass. In samples from Cephalorhynchus commersonii, the neritic Loligo gahi contributed 97.4% by number and 97% by dry mass and a neritic octopodinid contributed the rest of the cephalopod part of the diet. While the cephalopods contributed the major part of the diets of these particular cetaceans, other remains included fish and polychaete worms.

Growth of somatic tissue in Photololigo sp. was examined in terms of muscle fibre recruitment and growth. Muscle blocks and muscle fibres were measured and size frequency distributions compared between different size-classes of squid. Muscle blocks increased in size as individuals grew. The size frequency distribution of the muscle blocks suggested that this increase was due to both the generation of new muscle fibres and an increase in the size of existing muscle fibres. The size frequency distribution of muscle fibres was very similar in all size-classes of squid examined, and the presence of small muscle fibres in all individuals suggested that fibre recruitment may be continuous. Growth of muscle tissue, by muscle fibre growth and recruitment, provides a mechanism to explain constant growth throughout the life cycle described for tropical squid. Two structural types of muscle fibres, mitochondria-poor and mitochondria-rich, are present in juvenile and adult squid. A weak relationship between the ratio of the two muscle fibre types and dorsal mantle length suggests that generation of mitochondria-rich fibres may not be influenced by growth.

Squid of the genus Alloteuthis from the Aegean Sea and eastern Mediterranean were identified as A. media. It is not possible to distinguish A. media from A. subulata by relative fin length. Both ‘species’ are probably intraspecific forms. Egg size varied from 1·5 to 2·3 mm. Oocyte maturation in the ovary occurs in batches. The potential fecundity is some 1000–4000 eggs, most of these being released during continuous spawning accompanied by female growth.

Statoliths of Loligo gahi were sampled in the fishery region 45–47°S on the Patagonian shelf during September 1989. Peculiarities of the growth zones in the ground statoliths of adults are described. Maximum age of large maturing and mature females (130–160 mm of mantle length, ML) was estimated to be 325–345 d, that of large mature males (250–290 mm ML) ranged from 360 to 396 d.The squid Loligo gahi d'Orbigny, 1835, occurs in temperate shelf and upper slope waters of the Atlantic and Pacific coasts of South America and is caught commercially by the international fleet in the southern part of the Patagonian shelf within the Falkland Islands Interim Conservation Zone (FICZ) (Roper et al., 1984; Csirke, 1987). Occasionally, dense shoals of L. gahi appear in the fishery region 45–47°S off the Exclusive Economic Zone of Argentina (EEZA) and have been caught in significant numbers by trawlers at depths of 120–150 m in September-October (Chesheva, 1990). Loligo gahi is a medium sized loliginid; in Falkland waters males attain 350 mm ML, females 210 mm ML (Hatfield, 1991), while in the fishery region 45–47°S maximum size is 260 mm and 160 mm, respectively (Chesheva, 1990). Patterson (1988) revealed two Falkland spawning stocks of L. gahi of unclear status, spring-spawners and autumn-spawners (austral seasons) and pointed out that the life span of squid of each stock lasted ~1 y. Recently Hatfield (1991) used statoliths to elucidate Patterson's (1988) estimations of age and growth of Falkland stocks of L. gahi and confirmed the 1-y duration of L. gahi's life span.

9 páginas, 9 figuras, 4 tablas, Age, growth, and mortality were estimated for the first time in wild paralarvae of the common squid, Loligo vulgaris, by examining growth increments in the statoliths of 273 animals collected off the Ría de Vigo (NW Spain, NE Atlantic). Hatching was all year round for the period 2003–2005, with a peak during late spring and a secondary peak during early autumn. Paralarvae varied from 1260 to 7580 µm, and their abundance decreased abruptly as they grew. Statolith increments were clearly visible without grinding in almost all material, allowing reliable estimation of age. Paralarvae are planktonic for at least 3 months. Growth in dorsal mantle length (DML) during that period fitted an exponential equation. The instantaneous relative growth rates were 2.11, 2.15, and 1.82% DML d−1 for 2003, 2004, and 2005, respectively, and there were no significant differences in size-at-age between the 3 years. Taking into account the growth rates estimated for the whole cycle of L. vulgaris, we suggest that the lifespan may previously have been underestimated by 3 months, because the proximity of the rings deposited during paralarval and early juvenile stages would prevent accuracy in enumerating the number of growth increments in later stages. The estimated instantaneous rate of total mortality during the first 90 d of a paralarva life was 9.6, 5.3, and 4.8% d−1 for 2003, 2004, and 2005, respectively. Eye diameter was a reliable and rapid way of estimating DML and age, This research was funded by the CICYT (REN2002–02111/MAR and VEM2003–20010) and Xunta de Galicia (PGIDIT02–RMA–C40203PR) projects. Jaime Otero was supported by fellowships of the “Diputación Provincial de Pontevedra” and the European Social Fund-CSIC I3P postgraduate programme

The common European squid Loligo vulgaris is mainly caught by a bottom trawl fishery in the Gulf of Cadiz (SW, Spain), accounting for 2.6% of the total bottom trawl landings in the area. Squid landings from the bottom trawl fleet represent 99% of the total landings in the Gulf of Cadiz, while only 1% is caught by the artisanal fleet. The squid fishery by bottom trawl shows a clear seasonal pattern, with the higher landings of the species occurring in October and November. L. vulgaris is mainly distributed in the continental shelf, ranging between 15 m and 100 m depth. Biomass and abundance data were estimated from the ARSA bottom trawl surveys annually carried out in the Gulf of Cadiz in spring and autumn. Squid abundances estimated from these surveys were higher in autumn. The species shows a long reproductive period in the Gulf of Cadiz with mature females and males appearing during the whole year. The higher values were recorded during winter and spring. The estimated ML50 values for females and males were 18.9 cm and 16.3 cm, respectively. L. vulgaris shows a positive allometric growth, with females growing faster than males. The diet of the common European squid was studied from stomach contents collected in the ARSA scientific survey of November 2008. The osteichthyes group was the main component of the diet. Cephalopods and crustaceans were also present in the diet of L. vulgaris., Sí

Total concentrations of essential (Cu, Zn, Se and Cr) and non-essential (Hg, Cd, Pb and As) trace elements were measured in the flesh and hepatopancreas of Octopodidae (Eledone moschata, Eledone cirrhosa, Octopus salutii), Sepiidae (Sepia elegans, Sepia orbignyana) and Loliginidae (Illex coindeti, Loligo vulgaris) from the Mediterranean Sea. As expected, the hepatopancreas showed higher metal concentrations than flesh; the only exceptions were Hg and As, which were equally distributed in the two tissues. Regarding the edible portion, the highest toxic metal concentrations were in Octopodidae (Hg: 0.44, Cd: 0.49, Pb: 0.10 µg g(-1) wet weight) and Sepiidae (Hg: 0.27, Cd: 0.50, Pb: 0.12 µg g(-1) wet weight), while Loliginidae tended to accumulate less metal, especially Hg (Hg: 0.11, Cd: 0.30, Pb: 0.05 µg g(-1) wet weight). The other elements showed a heterogeneous distribution among the different cephalopod families. Loliginidae showed the highest Se concentrations (1.18 µg g(-1) wet weight), Octopodidae of Cu (37.37 µg g(-1) wet weight) and Zn (42.00 µg g(-1) wet weight) and Sepiidae of As (61.43 µg g(-1) wet weight), while Cr was uniformly distributed among the various families (0.38-0.43 µg g(-1) wet weight). In these seafoods, the concentrations of essential and non-essential elements were within the prescribed limits set by various authorities, except for Cu and As. Health risks posed by toxic elements to humans via dietary intake of these mollusks were assessed on the basis on Provisional Tolerable Weekly Intake (PTWI), while the estimated intakes of essential elements were compared to Dietary Reference Intakes (RDIs). A 70-g serving of these mollusks was shown to provide a large contribution to Cd intake (0.89 µg kg(-1) body weight), corresponding to 35.6% of PTWI. Concerning the essential elements, the consumption of these mollusks made an important contribution to daily dietary intake of Se, Cu and Zn.

Accessory nidamental glands present in female myopsid and sepioid species have been previously reported to harbour bacteria, and descriptions of the bacterial isolates were limited to morphology or pigmentation. As yet, no attempt has been made to describe the biochemical characteristics nor to identify the isolates. The accessory nidamental glands undergo a colour change during maturation which is attributed to the symbiotic bacteria. Since the colour of the bacteria in the glands has been reported to reflect the maturity state of the host, they are potentially useful in investigations examining factors influencing sexual maturation in cephalopods. The present study describes the physical and biochemical characteristics of bacteria isolated from the accessory nidamental glands of Loligo forbesi Steenstrup and utilizes the isolates in preliminary experiments to investigate factors controlling sexual maturation.

The timing of spawning and recruitment in the squid Loligo forbesi in Scottish waters is described on the basis of data from three sources: monthly samples of squid caught by commercial trawls (1986–1988), egg masses found by fishermen (1987–1991), and statistical data on animals caught by research trawls (1978–1987).Spawning females were present in samples from December to June, with peak spawning occurring in March. Most records of egg masses were from these months, but eggs were also found in August and September. These results suggest that there is an extended spawning season.Small squid (≤100 mm dorsal mantle length) were rarely present in commercial samples, but were recorded in research samples almost all year round. Thus there appears to be more or less continuous recruitment into the catchable population.The results of the present study are consistent with published data from other parts of the geographic range in that there is a regular seasonal peak in spawning, and spawning adults disappear from the population in summer. Further interpretation of the life-cycle of this species is not justified on the basis of current knowledge, and more information is needed on migrations, geographical variation, and lifespan in Loligo forbesi.

In Loligo forbesi Steenstrup, the female reproductive system consists of the ovary and accessory reproductive organs which include the oviducal gland, the nidamental gland, the accessory nidamental gland and seminal receptacle. Histological studies were made on the accessory reproductive organs of female L. forbesi. The various changes observed during maturation are described and the functional significance discussed. The secretions produced by the oviducal gland and nidamental gland apparently form the egg coats. The seminal receptacle serves to store spermatozoa after mating. The function of the accessory nidamental gland is unknown.

In order to protect and sustainably manage fishery resource species, it is essential to understand their movements and habitat use. To detect the hypothesised migration of maturing veined squid Loligo forbesi from the west coast of Scotland (UK) to the North Sea and identify possible inshore-offshore movements, we analysed seasonal, spatial and environmental patterns in abundance and size distribution, based on commercial fishery landings data and trawl survey data from Scottish coastal waters (International Council for the Exploration of the Sea, ICES areas IVa, IVb and VIa). A geographic information system (GIS) was used to build monthly contour maps of abundance. Generalised additive mixed models (GAMM) were used to quantify patterns in size distribution and abundance. In most years, there was no evidence of movement from the West to the East coast of Scotland. Evidence of inshore-offshore movements during the life-cycle of the cohort that recruits in autumn (winter breeders) was found instead. The winter breeding cohort appears to spawn in inshore waters and some evidence suggests that the spawning grounds of the summer breeders are also inshore. Across seasons, higher abundance of L. forbesi can generally be found in the north of Scotland at intermediate water depths and in warmer waters. info:eu-repo/semantics/publishedVersion

The population of Loligo forbesi inhabiting the Azorean Archipelago achieves the largest size ever reported for this species but also for any Loliginidae. Despite their importance as a food source for local communities, very little is known about their biology and ecology. In this paper, we describe our efforts in capturing, transporting, handling, tagging and holding wild adult L. forbesi in the laboratory. Three culture trials were conducted in the Island of Faial, Azores. Over 84 squid were captured by jigging, transported in separate containers and placed in a recirculating seawater system composed of three 3.6 m circular tanks (8000 l capacity each). Drawings and technical details about the system (filtration system, tanks, liners, illumination, flow rates, etc.) as well as water quality parameters (ammonia, nitrite, nitrate, iron, pH, salinity and temperature) are presented. By keeping squid in separate bags and providing constant water flow, no mortality occurred during transport from fishing ground to the laboratory. Mean survival time for each trial was 8 days (1503 g mean weight), 17 days (595.1 g mean weight) and 11 days (826.1 g). A small female remained alive for 44 days. In this system, mortality was faster for larger squid. Low survival time could be attributed to bad water quality management, namely high ammonia levels and high temperature variations but also restricted swimming space for larger squid (>1000 g). Pin tags proved to be the most adequate method of distinguishing between individuals. Squid were fed a variety of fish species, either fresh or defrosted. Daily feeding rates varied between 0 and 7.8% body weight (BW day−1). Most squid lost weight or did not grow. However, some individuals showed a positive increase in BW, varying between 0.009 and 1.4% increase in BW day−1. Key factors to take into account for increasing laboratory survival are: (1) catching squid with jigs; (2) prevention of skin damage during transport; (3) maintenance of small individuals; (4) segregating sexes to reduce agonistic interactions; (5) providing good water quality; and (6) abundant food supply.

Three consecutive generations of the oval squid, Sepioteuthis lessoniana, were cultured between October 2000 and May 2002 to investigate the life history of this species. Starting with the parental generation (wild-caught sub-adult squid from Tokushima Prefecture, Japan), we successfully obtained first and second generations. Life span and maturation of cultured oval squid and wild oval squid caught from the same habitat during April 2001 through to March 2002 were compared. Captive squid matured earlier and had a shorter life span (189–247 days) than the wild-caught squid (approximately one year) but reached an equivalent final body size. More ova were found in the oviducts of cultured females than in the oviducts of wild-caught females. Ultimately, collapse of the culture population was mainly due to the low rate of embryonic development of spawned ova, which might have resulted from the abnormal arrangement of ova in egg cases produced by later generations of females.

Squid on their spawning grounds feed mainly at night when they are more dispersed. In all, 28,5 per cent of squid sampled at night had food in their stomachs, whereas only 6,7 per cent of those collected by day had food. Most stomachs contained only a single prey species (90,8% of those analysed). Teleosts dominated the prey of squid collected at night (58%M), followed by crustaceans (25%), polychaetes (9%) and cephalopods (3%). By day the prey was dominated by cephalopods (61%), followed by teleosts (20%), crustaceans (14%) and polychaetes (2%). Bregmaceros sp. was the most frequently identified teleost, Loligo vulgaris reynaudii (cannibalism) the dominant cephalopod, ?Betaeus sp. (Alpheidae; pieces of coral were also found) the commonest crustacean and Nereis sp. the commonest polychaete. There were seasonal differences in the diet too: squid caught during summer seemed to have similar proportions of the four main prey components. Also, the incidence of feeding was higher than in winter. There were, how...

8 pages, 4 figures, 1 table.-- Printed version published Oct 2008., We characterised the most productive areas for the commercial squid Loligo vulgaris off the Catalan Coast based on the combined integration of SST and PAR satellite data. We present the distribution of these areas during the most productive months in relation to the spatiotemporal presence of paralarvae of this species off the Catalan Coast. The work is based on Generalised Additive Models (GAMs) that combine the simultaneous analysis of the effect of different environmental explanatory variables from satellite imagery data to obtain the optimal model for paralarvae of the squid. The proposed model helped define the potential Essential Fish Habitat (EFH) for squid paralarvae recruitment, based on the best environmental conditions and is consistent with the higher LPUE observed four months later. The EFH defined for paralarvae recruitment by the model was detected every year in May in the areas both north and central of the Catalan Coast, the same areas where fishing ports evidence the highest commercial yield of squid., This study was funded by the EU Project EnviEFH (FF6-SSP8-022466).

Changes in the ovaries and testes during sexual maturation of Loligo vulgaris reynaudii were examined histologically. Formation and development of the spermatozoa and oocytes could be divided into four distinct stages for males and five for females, and frequencies of these stages in the morphologically determined categories of development of the whole reproductive system were calculated. These frequencies were then compared between morphological categories. Results showed that microscopic changes are reflected in macroscale changes for Categories I–IV, but differences between Categories IV and V are mostly morphological for both sexes. It is suggested that Loligo v. reynaudii is an intermittent spawner.

Cephalopods are a taxonomic group that contains a great number of families, genera and species, with many of them very important at the commercial level. The existence of very similar species in this class added up to the transformation process applied to them makes it difficult or even impossible for species identification based on morphological characterization. Moreover, the global commerce makes it possible that one determined species can be marketed in its antipodes. These questions suggest the necessity of molecular techniques to solve this situation. In the present work, a genetic method was developed on the basis of the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and forensically informative nucleotide sequencing (FINS) technique and makes possible the identification of more than 20 species belonging to the families Ommastrephidae and Loliginidae, as well as some octopus and sepia species. The PCR was employed to amplify 651 and 208 bp fragments of the mitochondrial cytochrome b gene. These molecular systems were applied to fresh, frozen, precooked, even canned cephalopods, allowing for the identification of the species included in these products. Therefore, these molecular tools could be applied in questions related to correct labeling, traceability, and importation controls of squids, sepias, and octopuses.