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1.
An application of generalized linear models in production model and sequential population analysis 总被引：1，自引：0，他引：1
In fitting production models and age-structured models to an index of the relative abundance of a fish population, errors are usually assumed to follow a log-normal or normal distribution, without any diagnostic analyses. A generalized linear model can readily deal with many types of error structures. In this paper, a generalized linear model is coupled with a production model and a sequential population model to assess the stock of the Atlantic cod (Gadus morhua) 2J3KL. This study suggests that the parameter estimates in these models can be greatly influenced by the assumption about the error structures in the estimation and that log-normal and gamma distributions are appropriate for the production model in assessing the Atlantic cod 2J3KL stock, whereas gamma distribution is appropriate for the sequential population model. We recommend that generalized linear models should be used to identify the appropriate error structure in modeling fish population dynamics. 相似文献
2.
3.
John C. Field ré E. Punt Richard D. Methot & Cynthia J. Thomson 《Fish and Fisheries》2006,7(4):284-302
Marine protected areas (MPAs) have been increasingly proposed, evaluated and implemented as management tools for achieving both fisheries and conservation objectives in aquatic ecosystems. However, there is a challenge associated with the application of MPAs in marine resource management with respect to the consequences to traditional systems of monitoring and managing fisheries resources. The place‐based paradigm of MPAs can complicate the population‐based paradigm of most fisheries stock assessments. In this review, we identify the potential complications that could result from both existing and future MPAs to the science and management systems currently in place for meeting conventional fisheries management objectives. The intent is not to evaluate the effects of implementing MPAs on fisheries yields, or even to consider the extent to which MPAs may achieve conservation oriented objectives, but rather to evaluate the consequences of MPA implementation on the ability to monitor and assess fishery resources consistent with existing methods and legislative mandates. Although examples are drawn primarily from groundfish fisheries on the West Coast of the USA, the lessons are broadly applicable to management systems worldwide, particularly those in which there exists the institutional infrastructure for managing resources based on quantitative assessments of resource status and productivity. 相似文献
4.
Trevor J Kenchington 《Fish and Fisheries》2017,18(1):160-170
The Convention on Biological Diversity calls for networks of ‘representative’ MPAs, the effectiveness of which requires that the protected ecosystems be independent of external anthropogenic pressures. One principal pressure, fishing, severely depletes the oldest age classes of the target fish even if optimally managed. As many fishery resource species had high natural abundance and large individual sizes, while most fish show indeterminate growth and ascend the trophic pyramid as they grow, elimination of older age classes equates to removal of once‐dominant top predators. Because archetypal resource species are also migratory, that loss is transported throughout the range of the exploited populations, including into MPAs, through a lack of large migrants. The ecological implications remain uncertain in marine ecosystems, which are typically under ‘bottom‐up’ control. ‘Top‐down’ effects, such as mesopredator release, species replacement and trophic cascades, have been observed, however, meaning that elimination of top predators may affect ecosystem structure. It follows that, while exceptions doubtless exist, in general ‘representative’ MPAs should not be expected to fulfil their declared purposes, unless they are made so large as to encompass the whole migratory circuits of principal resource species – implying indefinite closure of the fisheries affected. Some compromise may be possible if MPAs were combined with fishing mortality rates far below current ‘optimal’ levels or where fishing can be concentrated on younger adults, while older fish are protected from exploitation. In any case, societies must choose between seafood production and recovery of selected marine areas to near‐pristine conditions. 相似文献
5.
Ingebrigt Uglem Pål Arne Bjørn Trine Dale Sven Kerwath Finn Økland Rune Nilsen Kåre Aas Ian Fleming & Robert Scott McKinley 《Aquaculture Research》2008,39(2):158-170
Commercial farming of Atlantic cod (Gadus morhua L.) is now being developed in several countries. The ecological consequences of cod culture are poorly understood, but recent research suggests that Atlantic cod are more prone to escape from net pens than Atlantic salmon. Here, we describe the movements and the spatiotemporal distribution of farmed cod after escape relative to wild cod, both during and outside the natural spawning season. The experimental design included simulating escape incidents of farmed cod tagged with acoustic transmitters and using an array of automatic listening stations to monitor their dispersal and distribution. For comparison, local wild cod were monitored using the same array of receivers. The farmed cod dispersed rapidly after a simulated escape, they randomly distributed over large areas and their distribution overlapped with local wild cod. Moreover, escaped farmed fish were found at local cod spawning areas during the spawning season. The study also indicated that the recapture rate of escaped farmed cod was high compared with that of escaped farmed salmon. Thus, while our results showed that there is a considerable potential for ecosystem effects caused by escaped farmed cod, mitigating actions such as an efficient recapture fishery for escapees may be possible. 相似文献
6.
Metapopulation ecology in the sea: from Levins' model to marine ecology and fisheries science 总被引：8，自引：0，他引：8
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. 相似文献
7.
Catherine Seytre Mathew A. Vanderklift Pascaline Bodilis Jean‐Michel Cottalorda Julien Gratiot Patrice Francour 《水产资源保护:海洋与淡水生态系统》2013,23(2):189-201
- Assessing both direct and indirect effects of fishing, i.e. effects extending to two or more trophic levels, is becoming a key issue in restoration ecology. The present study compared the Cap Roux no‐take area (NW Mediterranean) with the surrounding non‐protected areas.
- Direct effects of fishing were investigated using experimental net fishing and underwater visual census (UVC) specifically to survey species targeted by commercial fishing and angling. Indirect effects of fishing were deduced from predation and density of sea urchins.
- Observations showed higher biomass and abundance (from catch rates) inside the MPA and differences in size composition (from UVC). The effect of protection from fishing was rapid, with differences apparent within 5 years of protection, and was most evident for highly targeted fish.
- Rates of predation on two species of sea urchin (Paracentrotus lividus and Arbacia lixula) were dependent on protection level and season. This pattern was consistent with the presence of large Diplodus spp., known sea urchin predators, observed inside the reserve only in winter. However, the density of the sea urchins did not differ between the MPA and adjacent fished areas.
8.
Darienne Lancaster Philip Dearden Dana R. Haggarty John P. Volpe Natalie C. Ban 《水产资源保护:海洋与淡水生态系统》2017,27(4):804-813
- Marine conservation areas require high levels of compliance to meet conservation objectives, yet little research has assessed compliance quantitatively, especially for recreational fishers. Recreational fishers take 12% of global annual fish catches. With millions of people fishing from small boats, this fishing sector is hard to monitor, making accurate quantification of non‐compliance an urgent research priority.
- Shore‐based remote camera monitoring was tested for quantifying recreational non‐compliance in near‐shore, coastal rockfish conservation areas (RCAs) in the Salish Sea, Canada.
- Six high definition trail cameras were used to monitor 42 locations between July and August 2014.
- Seventy‐nine percent of monitored conservation area sites showed confirmed or probable fishing activity, with no significant difference in fishing effort inside and outside RCAs.
- Mixed effects generalized linear models were used to test environmental and geographic factors influencing compliance. Sites with greater depth had significantly higher fishing effort, which may imply high, barotrauma‐induced, rockfish mortality in RCA sites.
- Non‐compliance estimates were similar to aerial fly‐over compliance data from 2011, suggesting that trail camera monitoring may be an accurate and affordable alternative method of assessing non‐compliance in coastal conservation areas, especially for community‐based organizations wishing to monitor local waters.
- Widespread non‐compliance could compromise the ability of RCAs to protect and rebuild rockfish populations. Increased education, signage, and enforcement is likely to improve compliance.
9.
- Macroinvertebrates play a critical role in marine processes, are important in global fisheries, and make up the vast majority of ocean biodiversity, yet are largely overlooked in fisheries stock assessment and conservation. Marine reserves are a heavily advocated method for promoting recovery of marine biodiversity, but the design of reserves and the methods for evaluating their performance often neglect invertebrate taxa, instead assessing changes in fish abundance or biomass.
- The purpose of this study is to (1) measure the impacts of no‐take marine reserves on marine macroinvertebrates, (2) identify the correlates of changes to macroinvertebrate abundance, and (3) determine if the typical taxa used to measure reserve success (finfish) can predict changes in invertebrate abundance.
- Non‐coral, non‐sponge, macroinvertebrates were sampled inside and outside of 10 community‐managed marine reserves in the Central Philippines and compared with abundances found at distant fished sites.
- Using generalized linear mixed effects models with multimodel inference, positive reserve effects were found in exploited invertebrate taxa both inside and outside of reserves (1.5–2.3 times greater abundances), but no effect was found in unfished taxa.
- Habitat composition and complexity were consistently associated with higher invertebrate abundance. Most surprisingly, invertebrate abundance was not consistently predicted by that of fish.
- These results indicate fish, in isolation, may not be an ideal indicator for biodiversity response to reserves, and habitat considerations are important when creating reserves that support invertebrates. These results are particularly relevant to practitioners in developing regions, where community‐managed reserves are common and invertebrates are important in fisheries.
10.
- 1. Recreational shore fishing along the coast of the marine reserve of Cap de Creus (NW Mediterranean) was studied in 2007 and 2009 based on roving creel surveys (on‐site angler surveys during which anglers' harvests are examined by the survey clerk). The study aimed to assess the biological impacts of this leisure activity on coastal fish stocks and the potential risks arising from the use of exotic baits.
- 2. Recreational shore fishers employ seven different fishing techniques, of which the bottom fishing rod (a fishing rod whose hooks, together with the bait, lie on the bottom or near it by means of a heavy weight) is by far the most widely used method (nearly 90% of observations). In total, 25 fish species were identified in the catch from the bottom fishing rod.
- 3. The estimated annual shore fishing catches (c.3 tons) are much lower than those obtained by recreational boat and spear fishing (c.20 tons each), and those from commercial (artisanal) fishing (c.50 tons). The weighted mean vulnerability index and trophic level values in the catch from the bottom fishing rod are 52.2 and 4.03, respectively.
- 4. A minimum of 43% of the baits used by the shore anglers were live, non‐native species (mostly polychaetes).
- 5. Overall, results highlight the impact of shore angling on coastal fish communities of a protected area and the increasing environmental risks arising from the use of exotic marine baits, which constitute a potential and unregulated vector of introduction of non‐native species in the Mediterranean. Copyright © 2011 John Wiley & Sons, Ltd.
11.
Hamish A. Malcolm Alan Jordan Robert G. Creese Nathan A. Knott 《水产资源保护:海洋与淡水生态系统》2016,26(6):1090-1106
- Meta‐analyses of disparate studies suggest that size and age of a 'no‐take’ area (marine sanctuary) can influence its ecological response to protection. Few studies, however, have been designed explicitly to test how these factors influence the abundance trajectories of key species within sanctuaries.
- Diver surveys on reef habitat were conducted within a subtropical marine park in eastern Australia, to test for differences in abundances of targeted fishes between sanctuaries differing in size and age and compared with fished zones. Four management zones were sampled: (i) small sanctuaries established 1991 (<15 ha of reef and <200 m wide); (ii) large sanctuaries established 2002 (>100 ha of reef and > 500 m wide); (iii) zones which allowed recreational fishing but not commercial fish trapping (>200 ha of reef); and (iv) zones which allowed both recreational fishing and commercial fish trapping (>200 ha of reef). Multiple sites in each management zone were sampled for selected taxa eight times during the austral winter from 2002 to 2012.
- Many of the targeted taxa examined were more abundant in large sanctuary sites within a few years of the establishment of protection compared with the small sanctuary sites and the fished sites. Red morwong Cheilodactylus fuscus increased in large sanctuaries but were more abundant in the older smaller sanctuaries throughout the study. Similar increases were not observed in fished zones. There was considerable variability among years not associated with management type, including a peak in abundance for several species in 2005 and reduced abundance of many taxa following a destructive storm in 2009.
- This study provides strong empirical evidence that size and age of ‘no take’ areas are important for fish, and indicates that larger sanctuaries can rapidly reach levels of fish abundance similar to smaller older sanctuaries.
12.
- This work examined the potential for marine protected areas based on the efficient design of essential fish habitat (EFH) for juvenile life stages of economically important demersal fish species to represent non‐exploited demersal fish species in the Gulf of Maine.
- Distribution and abundance data from research trawl surveys conducted from 1963–2000 were pooled into a 10‐min lat/long square sampling grid and density per square of each species was calculated as the mean of counts from all surveys.
- A simulated annealing algorithm (Marxan) was used to identify minimum sets of 10‐min squares that represented at least 10–30% of the regional abundance of each species under constraints for degree of spatial aggregation among sites. Numbers of non‐exploited species in these sites, and species represented at abundance levels equal to or greater than the targets set for juveniles of economically important species were identified, and both were compared with mean totals from 100 sets of randomly drawn squares of equivalent number to simulation results.
- Percentages of non‐exploited species among all scenarios varied from 81–97%. All species absent from simulation results were rare regionally. Species richness was lower in each case compared with randomly drawn squares, but only marginally. However, more species were represented in complementary sites at abundance levels equal to or greater than the targets set for economically important species.
- These results were interpreted with respect to a definition of biodiversity that includes species as well as functional and structural ecosystem components, and it was concluded that the dual objectives of fishery management and biodiversity conservation can be achieved, at least in some cases, within a single network of marine protected areas of moderate size.
13.
A.P. MALOY S.C. CULLOTY M. BOLTON‐WARBERG R. FITZGERALD J.W. SLATER 《Aquaculture Nutrition》2011,17(5):536-541
The transition between endogenous and exogenous feeding in hatchery production of fish larvae has long been a bottleneck to increased production. Identification of alternative prey species with a wider array of nutritional profiles is essential for further expansion and diversification within the aquaculture industry. Traditional morphological methods to identify dietary composition are limited. In this study, we present a novel DNA‐based methodology for identifying the gut contents of larval fish that is independent of prey retaining identifiable characteristics. Laser capture microdissection is used to collect ingested material for DNA extraction, thus limiting contaminating DNA originating from the larval fish. PCR is then conducted using universal eukaryotic primers that have the potential to detect a wide diversity of prey items. Using this approach, we identified ingested Artemia salina from hatchery‐reared Gadus morhua larvae. Differential length amplification PCR was used to evaluate the effects of DNA degradation on the sensitivity of A. salina detection. Although it was possible to detect A. salina with relatively long (626 bp) fragments, targeting smaller fragments (264 bp) resulted in the highest return of prey sequences. This combined LCM and molecular approach to diet analysis could offer a more complete assessment of the diets of naturally feeding larvae. 相似文献
14.
Alan M. Friedlander Mary K. Donovan Haruko Koike Paul Murakawa Whitney Goodell 《水产资源保护:海洋与淡水生态系统》2019,29(Z2):103-117
- Ancient Hawaiians developed sophisticated natural resource management systems that included various forms of spatial management.
- The state of Hawai?i established its first legislated marine protected area (MPA) in 1953, and today there exists a patchwork of spatial marine management strategies along a range of sizes, with varying levels of governance, enforcement, and effectiveness.
- Approximately 12% of waters within the 50 m depth contour and 5% of waters within state jurisdiction (≤3 nmi) have some form of marine management. No‐take areas make up <0.5% of nearshore waters, and combined with highly protected areas account for 3.4% of this habitat. Most of the existing MPAs are small, with a median area of 1.2 km2 (confidence interval 0.2–8.1).
- Twenty‐five datasets, representing 1,031 individual surveys conducted throughout Hawai?i since 2000, were used to compare fish assemblage characteristics amongst a subset of MPAs using a regulation‐based protection classification scheme.
- Fully and highly protected areas had significantly greater resource fish biomass than areas with intermediate or low protection did. High human population density adjacent to MPAs had a negative influence on fish trophic structure within MPAs, whereas remote MPAs harboured higher fish biomass. Complex and heterogeneous habitats were important contributors to MPA effectiveness.
- Long‐term monitoring of select MPAs showed mixed and complex trajectories. Resource fish biomass increased after the establishment of the Hanauma Bay Marine Life Conservation District in 1967 but plateaued after ~15 years, followed by changes in assemblage structure from fish feeding and invasive species. The Pūpūkea Marine Life Conservation District, established in 1983, was expanded sevenfold in 2003 and showed dramatic increases in resource fish biomass following increased protection.
- This information is critical to improving effectiveness of existing MPAs, helping inform ongoing efforts to implement a network of MPAs statewide, and aiding in the development of comprehensive statewide marine spatial planning.
15.
Luca Appolloni Stanislao Bevilacqua Luisa Sbrescia Roberto Sandulli Antonio Terlizzi Giovanni Fulvio Russo 《水产资源保护:海洋与淡水生态系统》2017,27(4):828-838
- Although it is widely recognized that protection may enhance size, abundance, and diversity of fish, its effect on spatial heterogeneity of fish assemblages and species turnover is still poorly understood.
- Here the effect of full protection within a Mediterranean marine protected area on β‐diversity patterns of fish assemblages along a depth gradient comparing a no‐take zone with multiple unprotected areas is explored. The no‐take zone showed significantly higher synecological parameters, higher β‐diversity among depths, and lower small‐scale heterogeneity of fish assemblages relative to unprotected areas.
- Such patterns might likely depend on the high level of fishing pressure outside the no‐take zone, as also abundance‐biomass curves seemed to indicate. Results suggested that full protection could play a role in maintaining high β‐diversity, thus reducing the fragility of marine communities and ecosystems, and spatial heterogeneity may represent a reliable predictor of how management actions could provide insurance against undesirable phase shifts.
16.
Gotzon Basterretxea Ignacio A. Catalán Antoni Jordi Itziar Álvarez Miquel Palmer Ana Sabatés 《Fisheries Oceanography》2013,22(6):477-495
The factors that regulate the self‐recruitment of fish larvae were explored in Cabrera National Park (CNP), an insular Marine Protected Area (MPA) located off southern Mallorca (Western Mediterranean). Our study attributes the regulation of larval arrival to the MPA to a combination of retention by topographically generated circulation patterns around the island and shelf break frontal dynamics. Specifically, within the shelf, interaction of the wind‐induced oscillatory flow with the island was shown to generate ephemeral recirculation patterns that, over time, favor larval retention in the proximity of the MPA. According to our measurements, oscillatory flows produced by wind‐forced island‐trapped waves (ITWs) dominate the flow around CNP. ITW‐forced dispersion simulations were in agreement with the observed distributions of several typical fish species that breed in the CNP. A second regulator of environmental variability is the influence of boundary currents and open ocean mesoscale structures at the shelf break. These structures generate frontal zones that are comparatively more long‐lived than inner‐shelf circulation patterns, and they were shown to act as barriers to the offshore dispersion of coastal fish larval assemblages. Finally, inferences from larval size distributions around the MPA together with particle‐tracking model simulations suggested the relevance of behavioral processes for larval recruitment to the MPA. Based on these observations, the waters around the CNP can be viewed as a relatively stable system that allows breeding fish populations to rely on self‐recruitment for their long‐term persistence, independent of other source populations along the coast of Mallorca. 相似文献
17.
- Marine protected areas (MPAs), are being vigorously pursued globally but meeting significant resistance at a local level. Despite this, there is limited research into the factors that drive this resistance.
- The Port Stephens–Great Lakes Marine Park (PSGLMP) and Batemans Marine Park (BMP), both situated in New South Wales (NSW) Australia, were established in December 2005 and April 2006 respectively. Both generated significant controversy and hostility, particularly from the recreational fishing sector.
- The controversy surrounding the declaration of these and other NSW marine parks continues and has been the subject of intense political interest and government enquiry.
- Semi‐structured interviews were conducted with recreational, professional and indigenous fishers. They explored the social impacts of the declaration of PSGLMP and BMP and their link to marine park opposition. Opponents felt the marine parks had resulted in a variety of negative impacts ranging from a loss of enjoyment and convenience through to more serious impacts on wellbeing, livelihood and culture.
- Examination of the reasons why interview subjects participated in fishing provided further insight into their perception of the marine park and the impacts resulting from the declaration.
- Opposition to MPAs, however, cannot be explained by impact alone. All the marine park opponents interviewed represented themselves as ‘knowledge holders’ about their local marine area. This knowledge – predominately ‘fish’ knowledge – appears to have conflicted with a policy position which places biodiversity conservation as the primary objective of MPAs. This has led to a perception that the practical knowledge of users was not valued in the planning of each marine park.
- Incorporation of the goals and objectives of local communities into the development of MPA proposals may provide communities with a greater sense of ownership. Considering motivation to fish may allow for the development of more holistic management responses to mitigate and compensate users for social impacts that may arise from any necessary trade‐offs between these often competing objectives.
18.
Aaron J. Adams Justin P. Lewis Andrea M. Kroetz R. Dean Grubbs 《水产资源保护:海洋与淡水生态系统》2021,31(6):1346-1353
- A spatial approach to coastal management, such as marine protected areas, is being increasingly used to address biodiversity and fishery declines resulting from habitat loss, degradation, and overfishing. This approach is especially applicable in regions and fisheries that are data poor, and which often lack regulations and adequate capacity for enforcement. In data-poor situations, species that have economic, cultural, and charismatic value can provide leverage for ecosystem protection.
- In this study, acoustic telemetry was used to confirm a pre-spawning aggregation site, acting as critical information for protection of essential habitat for bonefish. Additionally, data sharing with an acoustic telemetry study on smalltooth sawfish (Pristis pectinata) documented linkages between the pre-spawning aggregation site and bonefish home ranges ≥70 km distant, thus providing an estimate of the catchment area.
- These data provided post hoc support for a marine national park designated in 2002, and demonstrate that the park is of the appropriate spatial scale.
19.
Manh Hung Pham Jacques Panfili Monique Simier Pauline Sindou Duc Huy Hoang Jean-Dominique Durand 《水产资源保护:海洋与淡水生态系统》2024,34(1):e4041
- Vietnam's oldest marine protected area, the Con Dao Archipelago, hosts a high diversity of fishes, but they are not taken into account in its management. Knowledge of the spatial and temporal diversity of fishes is critical to identify the ecological functions of protected habitats, including as nurseries and feeding grounds. One way to assess diversity is using light traps that target young fish stages.
- Fish were collected monthly from June 2016 to May 2017 using light traps in three main habitats: seagrass beds, coral reefs and the harbour. Morphometry and DNA barcoding were used to identify the species caught.
- A total of 11,293 fish were collected, of which 1,248 were barcoded and assigned to 158 species belonging to 81 genera and 34 families, evidence that coral reefs and seagrass beds in Con Dao marine protected area (MPA) are home to a highly diverse and abundant community of fish species. Species richness and Shannon diversity indices did not differ significantly among sampling sites, but both species composition and diversity indices differed in the wet and dry seasons. The abundance of fish was related to sea water temperatures, which varied significantly depending on the month. During the dry season, fish diversity peaked in April, when the water temperature was highest.
- Conserving fish in Con Dao MPA is important not only for the characterization of the trophic network in coral reefs and seagrass beds but also for preservation of coral reef ecosystems and endangered species. Ensuring connectivity between coral reefs and seagrass beds in Con Dao MPA would facilitate fish conservation but, at present, the MPA only focuses on protecting fragmented habitats that are home to a number of endangered mammal species. Local authorities should establish a continuum of protected areas along coastal habitats and seasonal controls on fishing as part of sustainable management of MPAs.
20.
Thomas Régnier Jane Dodd Steven Benjamins Fiona M. Gibb Peter J. Wright 《水产资源保护:海洋与淡水生态系统》2021,31(9):2381-2388
- Knowledge of vital data such as growth and age at maturity is necessary to develop effective management strategies for endangered species. The Critically Endangered flapper skate (Dipturus intermedius) is the largest skate in the North Atlantic and growth information, necessary to assess key life-history traits, populations’ growth rates and anticipate their response to management measures, is still lacking.
- While classical age estimation methods used in fish generally require the analysis of calcified structures, destructive methods are incompatible with conservation objectives for this species. Taking advantage of the high recreational value of the flapper skate, this study uses citizen-science data originating from photo-identification of trophy pictures and tag–recapture data supported by anglers to estimate growth in this Critically Endangered species. Using the growth increments measured between recapture events, an individual-based Von Bertalanffy growth model was fitted to the data using Bayesian inference.
- The results confirm that the flapper skate is a long-lived species with ages estimated as >40 years for the largest individuals captured. Despite this longevity, the model reveals a relatively fast initial growth but relatively late ages at maturity and significant sex-related differences in both growth rate and maximum size.
- These results suggest that population growth rate, and therefore recovery, might be much slower than previously reported. By using citizen science this study provides the necessary information to begin understanding population dynamics and monitor the recovery of an iconic Critically Endangered species.