Search

Within Cumberland Sound there are multiple stocks of Arctic Char (Salvelinus alpinus). This evaluation was performed to provide an updated summary of information available to assess the status of the Ikaluit Lake (Robert Peel Inlet) Arctic Char stock and recommend a long-term plan for the fishery. This waterbody was harvested as a test fishery from 1977 until 1982, as an exploratory fishery from 1983 until 1989, and as a commercial fishery (Schedule V) from 1990 until 2000, at which time the Pangnirtung Hunters and Trappers Organization (PHTO) requested that the commercial fishery be closed for a five-year period due to declining catches of larger Arctic Char. The initial quota was set at 1,500 kg for the test fishery and then reduced to 1,400 kg for the commercial licence. The Ikaluit Lake fishery was reopened in 2006 as an exploratory fishery with a reduced quota of 1,000 kg, where it currently remains. In this assessment there are four types of data presented from Ikaluit Lake: test fishery data; fishery-dependent data; fishery-independent data; and plant data. In addition to the licenced harvest, Ikaluit Lake Arctic Char are also harvested for subsistence purposes by both the community of Pangnirtung and the community of Iqaluit, however the rate of subsistence harvesting is not well documented. The results from this assessment suggest that the Ikaluit Lake Arctic Char stock is stable under present harvest levels. Consistency among recent years in Catch-Per-Unit-Effort (CPUE) data, weight-length relationships, length-frequency distributions, age-frequency distributions, mean trend data, length-at-age data, and age-at-maturity data support this conclusion. However, there are some signs that the stock is changing in response to fishing pressure as seen in the catch curves and instantaneous mortality rates over the years. Abundance modelling calculated a potential population size ranging from 4,288 to 9,594 individuals in the Ikaluit Lake stock. After applying a 5% threshold of the modelled abundance for sustainable harvesting (the 'Tallman Rule'), current harvest rates (not including subsistence fishing) are sustainable for the stock, however when subsistence fishing estimates are factored in, the stock becomes under significant harvest pressure. The recommendations for the long-term plan for Arctic Char in Ikaluit lake are to: more accurately account for subsistence harvesting in future assessments, continue close monitoring of the stock, ensure that future sampling is done in a consistent manner, and to collect and document the available traditional knowledge. [ABSTRACT FROM AUTHOR]

The status of Newfoundland and Labrador (NL) Atlantic Salmon populations are assessed relative to two reference points, defined on the basis of egg depositions, which separate three stock status zones (critical, cautious and healthy) as per the Fishery Decision-Making Framework Incorporating the Precautionary Approach. These reference points, the Limit Reference Point (LRP) and Upper Stock Reference (USR) point are set at 100% and 150% of the previously defined river-specific conservation egg deposition rate, respectively. In 2018, the status of Atlantic Salmon stocks within the NL Region (Salmon Fishing Areas 1-14B) was assessed using data collected from twenty-two rivers using a combination of salmon counting facilities (fishways and counting fences) and in-river snorkel surveys. Atlantic Salmon smolts migrating to sea were counted on five rivers in Newfoundland. The status of each monitored river is described by the designated stock status zone, % LRP achieved, and both short and long term trends in total adult salmon returns, smolt production and marine survival rates. Estimates of retained salmon in the 2018 recreational fishery were down by 70% and 58% compared to the previous generation averages in Newfoundland and Labrador, respectively. Labrador Food Social and Ceremonial (FSC) and subsistence fisheries harvests were estimated at 12,843 salmon in 2018 (8,762 small, 4,081 large), 7% less than the previous generation average. Of the twenty-two rivers monitored in 2018, one river was not included in the assessment due to an incomplete salmon count. Of the twenty-one other monitored rivers, sixteen had information on total returns over the previous generation (short term comparisons) and fifteen had information over the previous three generations (long term comparisons). Compared to the previous generation, total returns in 2018 were higher on three of four monitored rivers in Labrador and lower on five of twelve monitored rivers in Newfoundland. Compared to the previous three generations, total returns in 2018 were lower on one of four monitored rivers in Labrador and on five of eleven monitored rivers in Newfoundland. Conservation egg requirements were below the river-specific LRP (in the critical zone) on ten assessed rivers, between the LRP and USR on three assessed rivers, and above the river-specific USR on eight assessed rivers in the NL Region. Marine smolt survival is considered to be a major factor limiting the abundance of Atlantic Salmon within the NL Region. Smolt to adult survival of the 2018 smolt class ranged from <1% for Conne River to 9.3% for Western Arm Brook. [ABSTRACT FROM AUTHOR]

Body-element content was measured for three life stages of wild Atlantic salmon Salmo salar from three distinct Newfoundland populations as individuals crossed between freshwater and marine ecosystems. Life stage explained most of the variation in observed body-element concentration whereas river of capture explained very little variation. Element composition of downstream migrating post-spawn adults ( i.e. kelts) and juvenile smolts were similar and the composition of these two life stages strongly differed from adults migrating upstream to spawn. Low variation within life stages and across populations suggests that S. salar may exert rheostatic control of their body-element composition. Additionally, observed differences in trace element concentration between adults and other life stages were probably driven by the high carbon concentration in adults because abundant elements, such as carbon, can strongly influence the observed concentrations of less abundant elements. Thus, understanding variation among individuals in trace elements composition requires the measurement of more abundant elements. Changes in element concentration with ontogeny have important consequences the role of fishes in ecosystem nutrient cycling and should receive further attention. [ABSTRACT FROM AUTHOR]

Fecundity is an integral component of the calculation of Atlantic salmon, Salmo salar L., egg depositions in rivers. Fecundity determinations can be time consuming and prohibitively expensive in terms of application on a broad scale. Consequently, where river specific and annual data are not available, default means are used in calculations in Newfoundland and Labrador. It is important therefore to know the extent of variability among rivers, years and seasons and the potential error involved in using default values. Annual fecundity data were available for one river in Labrador and nine rivers in Newfoundland. Fecundity was determined from ovaries collected in the recreational fishery in the summer for all 10 rivers. For three of these rivers, fecundity determined from summer sampling was compared with that obtained from sampling at time of spawning in autumn. There was significant variability in fecundity with length as a covariate among rivers, years and seasons. Mean number of eggs per female decreased between 8.3% and 29.0% from summer to autumn while mean number of eggs per cm decreased from 5.0% to 28.5%. Depending on the measure of relative fecundity used (no. of eggs kg−1 or no. of eggs cm−1), results of simulations showed that estimates of egg deposition incorporating defaults can deviate from those obtained by applying year-specific and river-specific values by 50–75%, without adjusting for the seasonal reduction in fecundity, and by 30–50% with an adjustment. A sensitivity analysis revealed that of three parameters used in the calculation of egg deposition (size, percent female and fecundity), fecundity was the most influential. [ABSTRACT FROM AUTHOR]

The scales of three species of fishes, yellow perch Perca flavescens, walleye Sander vitreus and Atlantic salmon Salmo salar, were acidified and the isotopic signatures were compared to non-acidified scales from the same fishes. No significant acidification effects on either carbon or nitrogen isotope signatures were found. Results contrast with earlier literature findings noting significant acidification effects and suggest acidification tests be undertaken before scales are used for temporal reconstruction of fish food web positions. [ABSTRACT FROM AUTHOR]

Closure of the Newfoundland commercial Atlantic salmon,Salmo salarL., fishery in 1992 was the most restrictive measure introduced to help rebuild depressed local stocks of salmon. Here, the effects of the closure are evaluated by analysing trends in abundance since 1984, and estimates of survival in both freshwater and marine environments derived from enumeration of salmon at fish counting facilities. While freshwater production of smolts generally has been maintained, marine survival rates remain low (2–10%), and highly variable. Overall, total stock size differs little from that prior to the closure of the commercial salmon fishery. Spawning escapements have increased by a factor of 2 or 3 in some rivers, but in other areas total returns are lower on average than those prior to the fishery closure. Factors other than exploitation are contributing to lack of stock recovery, resulting in continued conservation concerns. [ABSTRACT FROM AUTHOR]

Marine exploitation rates were estimated for nine Newfoundland Atlantic salmon (Salmo salar L.) populations, separately for small and large salmon size components. Estimates were derived using counts of salmon returning to fish counting facilities rather than from tagging studies and thus adjustments were not required to account for tag loss, handling or tagging mortality, or tag reporting rates. For all stocks combined, the overall marine exploitation rate during the period 1984–1991 averaged 45.3% (29.6–57.1%) on small salmon and 74.2% (57.7–83.7%) on large salmon. These estimates are considered minimum values. Concerns related to declining salmon abundance resulted in the closure of the Newfoundland commercial salmon fishery in 1992. Results are discussed in relation to previous estimates derived from tagging, and highlight the importance of accounting for marine exploitation when examining trends in salmon survival and return data even when commercial fisheries have been closed. [ABSTRACT FROM PUBLISHER]

Five-thousand wild Atlantic salmon (Salmo salar L.) smolts from Conne River, Newfoundland, were captured during their downstream migration in May 1995, and transferred to an estuarine aquaculture rearing site at Roti Bay, 23 km away. Survival was monitored throughout the experiment. The greatest mortality occurred in July, approximately 6–8 weeks following transfer. Survival of smolts to one-sea-winter salmon was 18.5%, over four times higher than the average survival of wild salmon to Conne River during the past 6 years. Growth was monitored at monthly intervals until November 1995, with additional sampling in the spring and early summer of 1996. Survivors were split into two groups and released directly into the Bay d'Espoir fjord; one group was released 27–28 June 1996, at a site approximately 7 km from the mouth of Conne River. The second group was retained at Roti Bay and released 23 July 1996. Lotek radio transmitter tags were used in evaluating the success of the experiment by tracking migration timing and subsequent distribution of cage-reared salmon throughout the Conne River system. Approximately 80% returned to Conne River and 20% strayed to other streams. Less than 50% of the surviving fish were later accounted for in local Bay d'Espoir rivers. Results are discussed in relation to the utility of this technique to enhance salmon populations. [ABSTRACT FROM PUBLISHER]