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Fisheries monitoring in the United States exists in many forms and serves many functions due to geographically varying objectives, practices, technology, institutional structures, and funding. In the U.S and abroad, diverse catch methods commonly exist for the same stock, thus monitoring and reporting strategies need to be tailored to unique operational needs. Common management challenges include funding limitation, survey design, coverage, and implementation. We describe three innovative examples of fisheries monitoring in the United States. These stories of success and failure can inform the design and implementation of new monitoring pilots and aid crafting both regional and national policies. We explore the innovative vessel monitoring and electronic logbook practices across multiple sectors for Gulf of Mexico red snapper (Lutjanus campechanus). Then, we examine a unique monitoring program that produces critical, near real-time genetic and population surveys for sockeye salmon (Oncorhynchus nerka) in Bristol Bay, Alaska. Our final case study describes the many fishery-dependent and -independent data streams for American lobster (Homarus americanus) in New England. Across all monitoring cases exists an explicit focus on the most critical aspects of organism life history. We find strong cross-institutional working relationships and adept agency coordination are imperatives in instances of stocks occupying multiple state or federal boundaries. Our results suggest the most effective approaches address the unique data needs of a fishery, and for this, thorough understanding of both biological and socioeconomic aspects of the fishery is a prerequisite. Ultimately, the monitoring program should jointly incentivize compliance while promoting continued and evolving interaction between resources users, scientists, and management. Keywords: Fisheries, Fisheries monitoring, Fisheries management, Sustainability

Fisheries are complex systems comprised of scientific, management, fishing fleet, and ecological sub-systems. Although the composition, behavior, and functions of these sub-systems vary considerably, a review of case studies, research, and theory illustrates that one positive and pervasive influence across all can be at-sea monitoring of fishing activity and catch. At-sea monitoring provides reliable and high-resolution data on spatial and temporal patterns in effort and total catch, and the taxonomic and life stage composition of catch, thereby improving the science underlying management decisions. Those decisions can draw upon a wider range of approaches, such as rights-based management and finer scale spatial, temporal, and catch restrictions, that require the greater oversight facilitated by monitoring. Improved science and implementation can in turn increase confidence in management among the fishing fleet, bolstered by the knowledge that other fishers are equally accountable for their actions. This series of positive outcomes represent a self-reinforcing virtuous cycle in the fishery. Conversely, breakdowns in science, management, and fishing behavior can create an ‘accountability cascade’ of blame, distrust, and dysfunction. Therefore, effective at-sea monitoring, in combination with other reforms, can move fisheries away from overexploitation and toward sustainability. Critical to this transformation is a growing toolkit of technological innovations that increasingly make at-sea monitoring more feasible in fleets spanning diverse ecological, economic, political, and operational gradients. Keywords: Monitoring, Accountability, Uncertainty, Incentives, Compliance

Marine protected areas (MPAs) are a common management strategy for conserving marine resources, but it can be challenging to evaluate their effectiveness for meeting management objectives. Measuring the effectiveness of MPAs is particularly challenging in dynamic and changing environments where other management approaches are simultaneously implemented. Before–after–control–impact (BACI) analysis is a tool that offers a simple and robust design for evaluating complex effects. However, design and interpretation of a BACI analysis is not always straightforward. The goal of this study was to explore the potential for BACI to evaluate MPA performance in a system simultaneously impacted by other management measures and environmental change. We develop a typology of interpretations of BACI results based on the main and interaction effects of the model, categorized by the extent to which dynamics inside and outside of the MPA are independent. Furthermore, we examine how decisions about the spatial and temporal design of the study, and the focal species and response variables, can determine which outcomes from within the typology are evident through BACI applications to New England groundfish area closures. We identify strengths and limitations of the BACI approach and demonstrate that BACI is a valuable but imperfect tool for evaluating MPAs.

The decline of the Atlantic cod, Gadus morhua, stock in the Gulf of Maine to a historically low biomass has been coupled with a severe contraction in spatial range. The stock is now largely concentrated in the western Gulf of Maine. This erosion of spatial stock structure may be a factor-inhibiting recovery of Gulf of Maine cod. However, recent efforts to rebuild anadromous forage fish in the coastal Maine region coupled with the proposed creation of a new Eastern Maine Closed Area (EMCA), sited where localized depletion of the cod stock has been especially severe, might enable reestablishment of lost spatial structure of Gulf of Maine cod. We carried out larval transport modeling to examine the potential benefit of recovered cod spawning in the EMCA through supplying larvae to suitable juvenile settlement areas in the Gulf of Maine coastal zone and in the Cashes Ledge Closed Area (CLCA) in the central Gulf of Maine. The results indicate that an appreciable fraction of the larvae spawned in the EMCA are retained, to an age of settlement capability, in the coastal Maine region. Spawning in the EMCA may thus be a contributor of juveniles to a local, eastern Gulf of Maine, cod sub-stock. The results further indicate that spawning in the EMCA may supply a substantial subsidy of larvae to suitable juvenile habitat in the western Gulf of Maine and the CLCA. Protection of spawning stock in the EMCA may thus provide demographic benefits for the wider Gulf of Maine cod stock. Patterns of larval-stage connectivity between various potential spawning regions (including the EMCA) and areas of suitable juvenile habitat exhibit considerable interannual variability, which is predominantly linked to variability in the large-scale Gulf of Maine circulation. This result underscores the value of spatially explicit management as a means of fostering the recovery of the Gulf of Maine cod stock.

Multiple groundfish stocks in New England remain depleted despite management measures that have been effective elsewhere. A growing body of research suggests that environmental change driven by increasing concentrations of carbon dioxide in the atmosphere and ocean is unfolding more rapidly in New England than elsewhere, and is an important factor in the failure of these stocks to respond to management. We reviewed research on effects of changes in temperature, salinity, dissolved oxygen, pH, and ocean currents on pelagic life stages, post-settlement life stages, and reproduction of four species in the New England groundfish fishery: Atlantic cod (Gadus morhua), haddock (Melanogrammus aeglefinus), winter flounder (Pseudopleuronectes americanus), and yellowtail flounder (Limanda ferruginea). The volume of research on cod was nearly equal to that on the other three species combined. Similarly, many more studies examined effects of temperature than other factors. The majority of studies suggest adverse outcomes, with less evidence for mixed or positive effects. However, for all of the factors other than temperature, there are more knowledge gaps than known effects. Importantly, most work to date examines impacts in isolation, but effects might combine in nonlinear ways and cause stronger reductions in stock productivity than expected. Management strategies will need to account for known effects, nonlinear interactions, and uncertainties if fisheries in New England are to adapt to environmental change.

Recent advances in the application of stock identification methods have revealed inconsistencies between the spatial structure of biological populations and the definition of stock units used in assessment and management. From a fisheries management perspective, stocks are typically assumed to be discrete units with homogeneous vital rates that can be exploited independently of each other. However, the unit stock assumption is often violated leading to spatial mismatches that can bias stock assessment and impede sustainable fisheries management. The primary ecological concern is the potential for overexploitation of unique spawning components, which can lead to loss of productivity and reduced biodiversity along with destabilization of local and regional stock dynamics. Furthermore, ignoring complex population structure and stock connectivity can lead to misperception of the magnitude of fish productivity, which can translate to suboptimal utilization of the resource. We describe approaches that are currently being applied to improve the assessment and management process for marine fish in situations where complex spatial structure has led to an observed mismatch between the scale of biological populations and spatially-defined stock units. The approaches include: (i) status quo management, (ii) “weakest link” management, (iii) spatial and temporal closures, (iv) stock composition analysis, and (v) alteration of stock boundaries. We highlight case studies in the North Atlantic that illustrate each approach and synthesize the lessons learned from these real-world applications. Alignment of biological and management units requires continual monitoring through the application of stock identification methods in conjunction with responsive management to preserve biocomplexity and the natural stability and resilience of fish species.

This study investigated body size to fecundity relationships of a reef fish species targeted by line fishing, and examines the potential benefits of increased batch fecundity in no-take reserves compared to fished areas around the Palm, Whitsunday and Keppel Island Groups, Great Barrier Reef, Australia. Lutjanus carponotatus batch fecundity increased with fork length in a non-linear relationship that was best described by a power function. Batch fecundity differed by more than 100-fold among individuals, with a range from 7,074 to 748,957 eggs in fish ranging from 184 to 305 mm fork length. Furthermore, egg diameter increased with fish size. Based on underwater visual census, the potential batch fecundity per unit area in all three island groups ranged from 1.0 to 4.2 times greater in the no-take reserves than in the fished areas between 2001 and 2004. In 2002, a mean 2.3-fold difference in biomass between no-take reserves and fished areas converted to a mean 2.5-fold difference in batch fecundity per unit area. Greater batch fecundity, longer spawning seasons and potentially greater larval survival due to larger egg size from bigger individuals might significantly enhance the potential benefits of no-take marine reserves on the Great Barrier Reef.

We examined early life history traits and patterns of settlement of the slender filefish, Monacanthus tuckeri, at Calabash Caye, Turneffe Atoll, Belize. A settlement peak was evident at the new moon, and no settlement occurred at the full moon. However, settlement rates at the quarter moons could not be estimated due to sampling gaps. Many reef fishes show new moon settlement peaks, so M. tuckeri shares some characteristics with the primarily perciform species on coral reefs. Pelagic larval duration was long (mean = 42 days) and variable, suggesting that dispersal patterns might be diverse. Size at settlement was large (mean = 32 mm total length) and also variable. Larval duration and size at settlement were outside of the average values exhibited by reef fishes, but are not beyond the extreme end of the range, and might be explained by association with pelagic debris prior to settlement. There were no differences in overall settlement rates on reef and seagrass habitats, and fish settling to either habitat did not differ in larval duration, size at settlement, or larval growth rate. This suggests that settlement to alternative habitats may be random, or driven by availability of suitable microhabitat, rather than habitat quality or individual traits.

Environmental heterogeneity frequently induces spatial variability in somatic growth, which can cause inter-population differences in reproductive output among organisms for which fecundity is dependent upon body size. Mean asymptotic body size, L∞, varies among populations of several reef fish species. Deterministic models suggest L∞ has little effect on population growth, so subpopulations with larger L∞ may not have disproportionate effects in sustaining an open system. We used a stochastic simulation model to examine the potential role of a larger L∞ subpopulation in aspects of population dynamics beyond population growth under a range of assumptions about the prevailing recruitment relationships. We compared dynamics of a demographically homogeneous system with a system that included one subpopulation with 20% larger L∞. Despite the magnitude of the increase in L∞, mean population size and average time at large population sizes differed little between the homogenous system and that with the larger L∞ subpopulation. However, including the larger L∞ subpopulation did result in less time spent at very small population sizes, which could reduce extinction risks. Effects of the larger L∞ subpopulation were most pronounced when a deterministic recruitment cycle was imposed in combination with high stochastic variability in recruitment. This was due to regular series of poor recruitment years shifting the population structure toward older cohorts where differences in body size (and reproductive output) between the larger L∞ subpopulation and the other subpopulations were greatest. Differences were also greater when recruitment variability was regionally correlated. When recruitment variability was locally independent, the probability of system-wide declines was reduced because declines of individual populations at one time were replenished by unaffected neighbors in subsequent years. Our study suggests that variation in L∞ within a network of interconnected subpopulations may not be an important determinant of population behavior under certain conditions, but might be important in coping with periods of persistent, system-wide recruitment failure.

Studies examining the efficacy of marine protected areas (MPAs) rarely consider the potential for noncompliance. Violation of MPAs will typically occur near boundaries, so perimeter-to-area ratios will be important determinants of actual protection, suggesting that MPAs should be larger and likely fewer. If larval dispersal is highly localized, however, MPAs will need to be more numerous, widespread, and likely smaller in order to replenish many fished areas. Thus, there is a discord between the MPA network that would best achieve external replenishment and that which would maximize compliance. I investigated these competing criteria with a spatially structured model of a hypothetical marine fishery exploiting a sedentary reef-dwelling organism. With full compliance, a network of several small MPAs protects a population of similar size to that in a single large MPA and produces higher fishery yield across a range of fishing mortality rates. As noncompliance increases, however, the protected population in the network of several small MPAs approaches zero, whereas the single, large MPA population declines much less. Furthermore, at high levels of fishing mortality and noncompliance, yield with the network of several small MPAs begins to mirror that with no MPAs and drops below the yield with the single large MPA. Temporal variability in both the protected population size and yield are similar between the two designs with full compliance, but the single large MPA provides much greater stability in both metrics at high fishing mortality rates as noncompliance increases. My results highlight the important effects of noncompliance in realized MPA benefits and can explain why observed and expected effects might differ. Moreover, my results support a call for increased attention to rates of noncompliance and their ecological effects and greater collaboration among natural scientists, social scientists, managers, and stakeholders in understanding and altering illegal behavior. Resumen: Los estudios que examinan la eficacia de areas marinas protegidas (AMP) raramente consideran el potencial de incumplimiento. La violacion de AMP tipicamente ocurrira cerca de los limites, por lo que las relaciones perimetro:area seran importantes en la determinacion de la conservacion actual, lo que sugiere que las AMP deben ser mas grandes y posiblemente menos en numero. Sin embargo, si la dispersion larvaria esta muy localizada, las AMP deberan ser mas numerosas, mas dispersas y posiblemente mas pequenas para reestablecer muchas areas pescadas. Por tanto, hay una discordancia entre la red de AMP que mejor logre el reestablecimiento externo y que maximice el cumplimiento. Investigue estos criterios en competencia con el modelo estructurado espacialmente de una pesqueria marina hipotetica que explota a un organismo arrecifal sedentario. Con cumplimiento total, una red de varias AMP pequenas protege una poblacion de tamano similar al de una sola AMP grande y tiene mayor rendimiento pesquero en un rango de tasas de mortalidad por pesca. Sin embargo, a medida que aumenta el incumplimiento, la poblacion protegida en la red de varias AMP pequenas se acerca a cero, mientras que la declinacion de la poblacion en la unica AMP grande es mucho menor. Mas aun, en niveles altos de mortalidad por pesca y de incumplimiento, la produccion en la red de varias AMP pequenas comienza a ser similar a la de sin AMP y cae debajo de la produccion con la unica AMP grande. La variabilidad temporal tanto del tamano como la produccion de la poblacion protegida es similar en los dos disenos con cumplimiento total, pero la unica AMP grande proporciona mucha mas estabilidad en ambas medidas en tasas de mortalidad por pesca altas a medida que aumenta el incumplimiento. Mis resultados resaltan los efectos importantes del incumplimiento sobre los beneficios de AMP y pueden explicar porque pueden diferir los efectos observados y esperados. Mas aun, mis resultados son un llamado para mayor atencion a las tasas de incumplimiento y sus efectos ecologicos y para una mayor colaboracion entre cientificos naturales, sociales, administradores y publico para entender y alterar la conducta ilegal.

Marine and fisheries scientists are increasingly using metapopulation concepts to better understand and model their focal systems. Consequently, they are considering what defines a metapopulation. One perspective on this question emphasizes the importance of extinction probability in local populations. This view probably stems from the focus on extinction in Levins' original metapopulation model, but places unnecessary emphasis on extinction–recolonization dynamics. Metapopulation models with more complex structure than Levins' patch-occupancy model and its variants allow a broader range of population phenomena to be examined, such as changes in population size, age structure and genetic structure. Analyses along these lines are critical in fisheries science, where presence–absence resolution is far too coarse to understand stock dynamics in a meaningful way. These more detailed investigations can, but need not, aim to assess extinction risk or deal with extinction-prone local populations. Therefore, we emphasize the coupling of spatial scales as the defining feature of metapopulations. It is the degree of demographic connectivity that characterizes metapopulations, with the dynamics of local populations strongly dependent upon local demographic processes, but also influenced by a nontrivial element of external replenishment. Therefore, estimating rates of interpopulation exchange must be a research priority. We contrast metapopulations with other spatially structured populations that differ in the degree of local closure of their component populations. We conclude with consideration of the implications of metapopulation structure for spatially explicit management, particularly the design of marine protected area networks.

Gobiids are an abundant component of coral reef ichthyofauna, yet little is known of their life histories. I examined population structure, mortality and growth of the decorated goby, Istigobius decoratus, a common gobiid of shallow patch reefs on the Great Barrier Reef. Presumed daily increments in sagittal otoliths were used as a proxy for age. The upper age estimate was 266 days suggesting at most an annual life cycle. Instantaneous natural mortality rate estimates were 5.92 year−1 and 7.92 year−1 using two estimators, both corresponding to less than 1% annual survivorship. Specimens ranged from 12 to 84 mm total length. Analysis of size-at-age data indicated linear growth at a rate of 0.33 mm day−1. The linear relationship between size and age meant the population size structure mirrored the age structure with both skewed toward the smallest and youngest classes. High mortality over a 1-year longevity and linear growth suggest high population turnover and, therefore, that I. decoratus and ecologically similar species serve a potentially important role as prey species. This suite of traits is rarely reported for coral reef fishes, which is probably due to the limited attention paid to small-bodied species rather than the rarity of such a life history in these communities.

Density, population structure, mortality and growth of Lutjanus carponotatus on the Great Barrier Reef were compared on 2 spatial scales: between the Lizard and Palm Island groups and among 4 locations within the Palm group. The mean density at the Palm group was approximately 7 times that of the Lizard group. There were 2-fold differences in density within the Palm group, but strong statistical signals were not detected due to high variability in the data. Differences in size structures and asymptotic body sizes between the island groups were pronounced, and smaller differences were also evident within the Palm group. While age structures were similar among Palm group locations and lacked anomalous peaks, a series of strong cohorts at older age classes at the Lizard group suggests greater recruitment variability there during the past 2 decades. Variability in mortality did not increase with scale, as larger differences existed within the Palm group than between it and the Lizard group. The population traits estimated in this study were used in conjunction with reef area data to generate estimates of abundance and biomass, the values of which illustrate how multiple population traits interact to ultimately determine population size and reproductive potential. Multi-scale studies that examine a variety of aspects of population biology are rare for large reef fish, but are needed to identify which traits are likely to exhibit variation on which spatial scales.

The purpose of this chapter is to consider the question “Is it necessary to validate the periodicity of increment formation in every species of fish for which we seek age-based demographic data”? The focus is on coral reef fishes. Four issues require consideration. Firstly, validation programs are expensive in terms of resources and time. This is especially important for coral reef fishes as resources available to tropical fisheries are often very limited. Secondly, many modern techniques used to validate the accuracy of age estimates require field and laboratory infrastructure that may not be available to fisheries laboratories serving coral reefs. Thirdly, the great majority of validation studies have confirmed the annual periodicity of increment formation. Fourthly, opportunities to study undisturbed populations of reef fishes from which reference age data can be derived are limited due to over-fishing and habitat alteration. We argue for a more strategic approach to age-based studies in coral reef fishes.

Publisher Summary The ecology of coral reef fishes seems to invite a metapopulation perspective. A metapopulation structure is determined by the spatial arrangement of local populations, coupled with life-history traits that allow metapopulation dynamics to be enacted. There certainly is evidence to suggest that coral reef fishes may form metapopulations, at least when metapopulations are defined with reference to spatial structure and connectivity rather than extinction recolonization dynamics. Extinction recolonization may be evident at the edge of species ranges, such as within the Capricorn Bunker group of the Great Barrier Reef. Metapopulation dynamics are viewed as something more than extinction recolonization dynamics, and greater potential is seen for the presence of metapopulations among coral reef fishes. Demographic traits and behavior can vary even among very proximal populations, or among adjacent reef zones, reflecting a part of the independence of these populations. The population dynamics that result from dispersal patterns and local demography typically show asynchrony among populations, at least as indicated by recruitment data. To provide better answers, reef fish ecologists need, first and foremost, to continue the burgeoning trend of large-scale, interdisciplinary research on larval dispersal and demographic connectivity. At the same time, one should not accept too blindly the assumption that postsettlement reef fishes are sedentary; one should be looking to test this assumption in situations where it is likely to be violated.

Publisher Summary The Merging of Metapopulation Theory and Marine Ecology This chapter considers three general explanations for the pattern of use of metapopulation ideas in marine ecology. The chapter examines whether there are fundamental differences between marine and terrestrial systems that limit the use of theory developed primarily in one context for use in the other context. Such an examination is done through a critical assessment of how metapopulation theory is used in terrestrial ecology and suggests likely differences in the application of metapopulation theory to marine systems. The slow adoption of a metapopulation paradigm in marine ecology might have been a direct consequence of the pattern of development of ideas. Questions in marine ecology have been explored, and the extent to which marine environmental management and conservation may have helped initiate and now continue to drive the application of metapopulation theory has been examined. Although it might be logical for marine ecology and fisheries management science to interact closely, there has been a long history of marine ecology borrowing concepts and theories from terrestrial ecology. Although marine and terrestrial systems have in common the fact that populations are patchily distributed, it is clear that marine systems differ from terrestrial ones. Marine ecology came to adopt metapopulation theory by way of its rediscovery of the importance of larval dispersal and recruitment dynamics.

Publisher Summary This chapter reviews the question of whether marine and terrestrial systems have such fundamentally different characteristics that metapopulation theory is useful only on land, or at least to require drastically different constructs in the concepts and models. But there are marine systems that possibly should not be seen as metapopulations. A nonexhaustive list of key research topics that need to be addressed to build a better understanding of metapopulation structure and dynamics in the sea is provided. The interaction between marine metapopulation ecology and management of living marine resources is also considered. Drawing upon metapopulation theory should continue to present new questions and guide new marine ecological research. Marine systems can, at the very least, increase the range of variation on the basic and universal set of population processes represented in metapopulation studies, and marine ecologists can substantially widen the pool of scientists focused on metapopulation issues.

A central aim of ecology is to explain the heterogeneous distribution of biodiversity on earth. As expectations of diversity loss grow1,2,3,4,5, this understanding is also critical for effective management and conservation. Although explanations for biodiversity patterns are still a matter for intense debate5, they have often been considered to be scale-dependent6,7. At large geographical scales, biogeographers have suggested that variation in species richness results from factors such as area, temperature, environmental stability, and geological processes, among many others5,7,8,9,10,11,12,13,14. From the species pools generated by these large-scale processes, community ecologists have suggested that local-scale assembly of communities is achieved through processes such as competition, predation, recruitment, disturbances and immigration5,6,7,8,15,16. Here we analyse hypotheses on speciation and dispersal for reef fish from the Indian and Pacific oceans and show how dispersal from a major centre of origination can simultaneously account for both large-scale gradients in species richness and the structure of local communities.