Parrotfish Size: A Simple yet Useful Alternative Indicator of Fishing Effects on Caribbean Reefs?

There is great need to identify simple yet reliable indicators of fishing effects within the multi-species, multi-gear, data-poor fisheries of the Caribbean. Here, we investigate links between fishing pressure and three simple fish metrics, i.e. average fish weight (an estimate of average individual fish size), fish density and fish biomass, derived from (1) the parrotfish family, a ubiquitous herbivore family across the Caribbean, and (2) three fish groups of “commercial” carnivores including snappers and groupers, which are widely-used as indicators of fishing effects. We hypothesize that, because most Caribbean reefs are being heavily fished, fish metrics derived from the less vulnerable parrotfish group would exhibit stronger relationships with fishing pressure on today’s Caribbean reefs than those derived from the highly vulnerable commercial fish groups. We used data from 348 Atlantic and Gulf Rapid Reef Assessment (AGRRA) reef-surveys across the Caribbean to assess relationships between two independent indices of fishing pressure (one derived from human population density data, the other from open to fishing versus protected status) and the three fish metrics derived from the four aforementioned fish groups. We found that, although two fish metrics, average parrotfish weight and combined biomass of selected commercial species, were consistently negatively linked to the indices of fishing pressure across the Caribbean, the parrotfish metric consistently outranked the latter in the strength of the relationship, thus supporting our hypothesis. Overall, our study highlights that (assemblage-level) average parrotfish size might be a useful alternative indicator of fishing effects over the typical conditions of most Caribbean shallow reefs: moderate-to-heavy levels of fishing and low abundance of highly valued commercial species.     

闽南-台湾浅滩渔场二长棘鲷群体景观多样性

根据1998年7月到2000年6月闽南-台湾浅滩渔场开展二长棘鲷资源的专项调查资料,以各个渔区CPUE(Catch Per Unit Effort)及其到渔场重心距离为参数,构建基于渔场重心动能的景观要素,运用景观多样性,并结合因子分析,分析了二长棘鲷群体景观多样性的空间格局及其与海洋环境因子之间的关系,探究了种群空间分布格局与生态过程之间的相互作用关系,旨在揭示闽南-台湾浅滩渔场二长棘鲷的生态境况及空间变异特征,为从生态水平上合理综合利用二长棘鲷渔业资源提供新的依据。结果表明:(1)不同月份鱼群的分布特征差别明显,8月鱼群分布范围最广,11月鱼群分布最为均匀,2月和12月鱼群分布最集中,而9月鱼群占据渔场空间能力最强;(2)不同群体之间具有不同分布特征,生殖群体分布范围最小,且最集中,其占据渔场空间能力最弱,幼鱼群体分布范围小,且相对均匀,其占据渔场空间能力强,索饵群体分布范围最广,且较均匀,鱼群分散索饵,其占据渔场空间能力最强,而9—11月群体平均分布范围较广,且最均匀,其占据渔场空间能力较弱;(3)鱼群综合景观指数是具空间结构的CPUE指数,从生态水平上反映了鱼群CPUE,其排名依次为8月、6月、7月、9月、10月、11月、5月、1月、4月、3月、2月、12月;(4)多样性指数、均匀度指数和优势度指数指示的生态学意义分别为鱼群的分布范围、均匀程度和鱼群空间竞争能力,其中多样性指数和均匀度指数呈正相关;(5)水温是影响鱼群景观均匀度的主要因子,索饵是增加鱼群景观多样性和优势度的主要因子,而生殖因子则降低鱼群景观多样性和优势度,水温、索饵和生殖是二长棘鲷群体景观格局变化的主要驱动因素。     

Length-dependent changes in egg size and fecundity in females, and brooded embryo size in males, of fork-tailed catfishes (Pisces: Ariidae) from the Sepik River, Papua New Guinea, with some implications for stock assessments

Data suggest that mature egg weight is positively correlated to female parent length in all five species of fork-tailed catfish studied. Embryo weight is positively correlated with the length of the male mouthbrooding parent in the four species where data are available. Non-random mate pairing is probably between fish of equivalent size. Fecundity appears to be linearly related to female fish length in all species. There is no significant correlation between fecundity and female weight, probably because egg size increases with fish size. Low fecundities and breeding behaviour suggest that recruitment is likely to be highly density-dependent and the stocks vulnerable to increased mortality (fishing). Changes in egg size with fish size may account for deviations from a cube relationship between fecundity and fish length in other species. The relevance of this to other fish stock assessments is discussed. Attention is drawn to possible changes in egg size with fish length which could affect recruitment in fished stocks, depending on the specific relationship and the length at which mature fish are caught.     

Diet and scavenging habits of the smooth skate Dipturus innominatus

The diet of smooth skate Dipturus innominatus was determined from examination of stomach contents of 321 specimens of 29·3-152·0 cm pelvic length, sampled from research and commercial trawlers at depths of 231-789 m on Chatham Rise, New Zealand. The diet was dominated by the benthic decapods Metanephrops challengeri and Munida gracilis, the natant decapod Campylonotus rathbunae and fishes from 17 families, of which hoki Macruronus novaezelandiae, sea perch Helicolenus barathri, various Macrouridae and a variety of discarded fishes were the most important. Multivariate analyses indicated the best predictors of diet variability were D. innominatus length and a spatial model. The diet of small D. innominatus was predominantly small crustaceans, with larger crustaceans, fishes and then scavenged discarded fishes increasing in importance as D. innominatus got larger. Scavenged discards were obvious as fish heads or tails only, or skeletal remains after filleting, often from pelagic species. Demersal fish prey were most frequent on the south and west Chatham Rise, in areas where commercial fishing was most active. Dipturus innominatus are highly vulnerable to overfishing, but discarding practices by commercial fishing vessels may provide a positive feedback to populations through improved scavenging opportunities.     

Spatio-Temporal Dynamics of Exploited Groundfish Species Assemblages Faced to Environmental and Fishing Forcings: Insights from the Mauritanian Exclusive Economic Zone

Environmental changes and human activities can have strong impacts on biodiversity and ecosystem functioning. This study investigates how, from a quantitative point of view, simultaneously both environmental and anthropogenic factors affect species composition and abundance of exploited groundfish assemblages (i.e. target and non-target species) at large spatio-temporal scales. We aim to investigate (1) the spatial and annual stability of groundfish assemblages, (2) relationships between these assemblages and structuring factors in order to better explain the dynamic of the assemblages’ structure. The Mauritanian Exclusive Economic Zone (MEEZ) is of particular interest as it embeds a productive ecosystem due to upwelling, producing abundant and diverse resources which constitute an attractive socio-economic development. We applied the multi-variate and multi-table STATICO method on a data set consisting of 854 hauls collected during 14-years (1997–2010) from scientific trawl surveys (species abundance), logbooks of industrial fishery (fishing effort), sea surface temperature and chlorophyll a concentration as environmental variables. Our results showed that abiotic factors drove four main persistent fish assemblages. Overall, chlorophyll a concentration and sea surface temperature mainly influenced the structure of assemblages of coastal soft bottoms and those of the offshore near rocky bottoms where upwellings held. While highest levels of fishing effort were located in the northern permanent upwelling zone, effects of this variable on species composition and abundances of assemblages were relatively low, even if not negligible in some years and areas. The temporal trajectories between environmental and fishing conditions and assemblages did not match for all the entire time series analyzed in the MEEZ, but interestingly for some specific years and areas. The quantitative approach used in this work may provide to stakeholders, scientists and fishers a useful assessment for the spatio-temporal dynamics of exploited assemblages under stable or changing conditions in fishing and environment.     

Factors related to gizzard shad and the threadfin shad occurrence and abundance in Florida lakes

Gizzard shad Dorosoma cepedianum were collected in 23 and threadfin shad D. petenense were collected in 22 of the 60 Florida lakes sampled. Logistic regression equations were 94% effective for predicting gizzard shad occurrence from chlorophyll and lake surface area, and 84% effective for predicting threadfin shad occurrence from lake surface area and lake volume inhabited (PVI). Occurrence of both shad species was related positively to lake size. In lakes where gizzard shad or threadfin shad were collected, shad density and biomass of both shad species were related positively to chlorophyll. Gizzard shad populations were generally vulnerable to predation in lakes, with the per cent of gizzard shad ≤200mm L _T values exceeding 60% with few exceptions. Effects of gizzard shad and threadfin shad on fish community dynamics may be confined to relatively large (>100 ha) and fertile (chlorophyll >20–30μg l⁻¹) Florida lakes.     

The Variation in the Acidity of Ground and Surface Waters in Northern Ireland

The distribution of surface and ground waters in Northern Ireland were mapped with respect to pH and total hardness and the distributions discussed in relation to the regional geology and pedology. These waters were grouped into 3 categories depending on their vulnerability to acidification. Three upland areas, the Mournes, the western Sperrins and the northern Glens of Antrim, were identified as being vulnerable to acidification. Concentrations of total and labile aluminium in these areas were high and, in the Mournes and Sperrin areas, exceeded the EC directive on total aluminium in drinking water. However, because of their differing geology and pedology, only the Mournes area had labile aluminium levels which gave cause for concern. A fish survey in a reservoir in the Mournes catchment showed that it supported a small but self-sustaining population of brown trout (Salmo trutta) which, although small in size, showed no signs of deformity.     

The northern gannet (<Emphasis Type="Italic">Morus bassanus</Emphasis>, Pelecaniformes,Sulidae) in the Black Sea in the Late Holocene

Fossil remains of gannets were found during excavations in the port area of the ancient city of Chersonesus (Sevastopol) in the layers dating to the 5th and 10th centuries AD. Judging by the joint findings of gannet bones and those of other marine fish-eating diving birds, they had been captured in fishing nets, where they died while diving for fish. The species composition of the aquatic birds accompanying the findings of gannets suggests that gannets appeared on the northern coast of the Black Sea mainly during cold seasons. The distribution and number of findings of gannets in the northern Black Sea region indicates that these birds were widespread there. Gannets could have appeared in the Black Sea from the Mediterranean Sea penetrating there from the Atlantic Ocean during long eastward migrations. Gannets appeared in the fauna of the Black Sea no later than the 6th century BC and became extinct no earlier than the tenth century AD, probably surviving up until the 14th–15th centuries AD.     

Invasive pike establishment in Cook Inlet Basin lakes,Alaska: diet,native fish abundance and lake environment

Northern pike (Esox lucius) were introduced to the northern Susitna Basin of south-central Alaska in the 1950’s, and have since spread throughout the upper Cook Inlet Basin. Extirpations of several native fish populations have been documented in this area. It is hypothesized here that invasive pike remodel the ecology of lakes by removing vulnerable prey types and that these changes are reflected in the diet of invasive pike. Trends in pike diet suggest that pike switch to less desirable but more abundant macroinvertebrate prey as preferred fish prey are eliminated. The impacts of pike introduction were studied in detail for one species of resident fish, the threespine stickleback (Gasterosteus aculeatus). Stickleback abundance decreases as pike invasion progresses. Conductivity is a significant environmental predictor of stickleback abundance, with higher conductivity apparently mitigating population reduction. Higher conductivity water may lessen the physiological costs of developing more robust armor, which reduces vulnerability to predation. Maximum lake depth also appears to predict stickleback abundance, though this trend was only marginally significant. Deeper lakes may provide an open-water refuge from pike predation by allowing stickleback to exist outside of the pike inhabited littoral zone. These findings indicate the importance of diverse habitat types and certain chemical and physical characteristics to the outcome of invasion by fish predators.     

渔场重心信度测算及渔场重心修正理论构建——以闽南-台湾浅滩渔场二长棘鲷为例

渔场重心是表征渔场位置的重要参数,准确掌握渔场重心,对判断鱼类洄游路线、确定中心渔场、表征鱼群分布特征和变化规律具有重要意义。渔场重心计算采用的是固定物体重心计算方法,然而运动的鱼类和固定物体有着本质的区别。因此,由固定物体重心计算的渔场重心能否体现鱼群分布特征,值得深入研究。渔场重心信度是用于度量由固定物体重心计算的渔场重心表征鱼群分布特征的能力,体现渔场重心的可信程度,而渔场重心修正是为了提升渔场重心表征鱼群分布特征的能力,提高渔场重心信度,以准确掌握渔场重心。以闽南-台湾浅滩渔场二长棘鲷(Parargrops edita Tanaka)为例,采用渔场重心、几何中心和单位捕捞努力量渔获量(Catch Per Unit Effort,CPUE)为参数,首次建立了渔场重心信度测算及渔场重心修正理论和方法,分析了渔场重心信度,研究了渔场重心修正方法和渔场重心的分布特征,旨在从更精细地水平上掌握二长棘鲷渔场重心,为生态智慧在渔业资源开发和管理的应用提供可靠的数据支持。结果表明:(1)二长棘鲷渔场重心信度各月变化在0.12—1.00,平均值0.67,均方差0.31,各月渔场重心可信度波动较大,12月份和2月份渔场重心信度最大为1.00,鱼群对称和均匀分布于渔场重心,渔场重心可信度最高,3—8月份渔场重心信度低于0.70,鱼群在渔场重心周围的对称性和均匀度差,渔场重心可信度差,其中3月份渔场重心信度最小为0.12;(2)渔场重心信度不仅反映了渔场重心可信程度,还体现了鱼群在渔场重心周围的分布特征,可作为研究鱼群分布特征的重要参数,渔场重心信度低于0.70,渔场重心需要修正;(3)渔区修正系数用于判别鱼群所在渔区是否排除,通过去除渔区修正系数小于0.5的鱼群,能保留85%以上的鱼群数量,提高渔场重心信度0.70以上;(4)修改后的渔场重心变化规律较显著,4—5月份,幼鱼群体重心向西迁移,6—7月份,索饵群体重心向东北方向移动,8月份,索饵群体重心开始往南迁移,9—11月份,越冬群体重心逐渐向南移动,12月份,生殖群体重心继续往南迁移,1—3月份生殖群体主要集中在305渔区(119°15'E,23°15'N)附近进行生殖活动,鱼群少有迁移。     

Gear selectivity of functional traits in coral reef fisheries in Brazil

Small-scale reef fisheries are important commercial and subsistence activities that support the livelihoods of millions of people in tropical regions. Tropical marine fisheries typically target a diversity of species caught with a matching diversity of fishing gears and practices. Here, we explored how multiple fishing gears select for distinct functional traits of fish assemblages inside a large multiple use marine environmental protected area off northeastern Brazil. In 1833 landing interviews with local fishers, we identified 101 species, which were categorized according to six traits: body size, schooling behavior, mobility, position in the water column, diet and period of activity. Our research is the first to explore the broad patterns of gear selectivity with regards to fish functional traits for different habitat types. While gears used in reef habitats were highly selective of sedentary and benthic species that form schools with few individuals, gears used in coastal lagoons were selective of highly mobile pelagic species that form large schools. We found a low competitive interaction between different gear types, meaning there was a low overlap in trait selectivity between fishing gears. We also found direct associations between gears and fish functional traits: hooks and line targeted species that exhibit limited mobility capabilities, making these species more vulnerable to local levels of fishing effort. In contrast, nets and fish corrals targeted mobile species that exhibited a greater diversity of functional traits. Some of our results contrasted with the current literature on the topic, with differences highlighting the need for more research to clarify global patterns of trait selectivity by gear type. Our results have implications for fisheries management in northeastern Brazil: gear bans and effort caps are commonly used management measures that can foster fisheries sustainability by minimizing impacts to fish assemblage functions.

     

Underwater predatory behaviour of the American mink (Mustela vison)

Fishing behaviour of the American mink ( Mustela vison Schreber) was investigated in the laboratory. Data were recorded using ciné film and tape recorded commentaries. Three species of prey were presented to mink, namely, carp ( Cyprinus curpio ), goldfish ( Carassius auratus ) and minnows ( Phoxinus phoxinus ).
It was found to be necessary to train ranch-bred mink to enter water and catch fish; young mink appeared to be easier to train than adults. Mink spent 5–20 sec under water when fishing; prey had usually previously been located from an aerial vantage point. Predatory behaviour was highly organized sequentially whereas fish were more prone to indulge in unpredictable stratagems; the behaviour of mink and fish were highly correlated.
The mink's efficiency in catching fish was related to prey size (smaller individuals being more vulnerable to capture) and shoaling. Minnows, which form highly organized shoals, were less easily caught when present in large numbers; this was not true of a loosely shoaling species, the carp.
Of the three species of prey presented, vulnerability to capture took the form goldfish> carp> minnow; these differences, however, may have been influenced by the fish's previous experience of underwater predators.     

Assessing the potential biological implications of recreational inshore fisheries on sub‐tidal fish communities of Azores (north‐east Atlantic Ocean) using catch and effort data

Recreational inshore fishing activities practiced on Faial and Pico Islands (Azorean archipelago) were surveyed between October 2004 and September 2005. Recreational inshore fishers employ three main methods of fishing (shore angling, spear fishing and intertidal collecting). The method that demanded the highest fishing effort (number of fishing operations) was shore angling, followed by intertidal collecting and spear fishing. Shore angling produced the highest diversity of catch composition (38), which is in part explained by the seven fishing techniques used by shore anglers. The estimates of annual catch were higher for shore angling than spear fishing (51·2 and 6·3 t) even though they were lower than commercial artisanal fishing (442 t). The weighted mean trophic level and vulnerability index values in the fish catch were higher for spear fishing (3·4 and 50·9) than for shore angling (3·1 and 44·5). Cumulative pressure by different recreational fishing activities was detected on species already subject to a heavy pressure from Azorean commercial fishing, and on vulnerable and top‐predator species. There are important biological and ecological implications whereby fishery managers should implement additional regulations such as prohibiting catches of the most vulnerable species.     

Comparative size and composition of yield from six Fijian reef fisheries

The size and composition of finfish yield from six Fijian reef fisheries was determined using catch records from a voluntary logbook scheme. A total of 172 logbooks were issued for 30-day periods in October 1992 and February and June 1993 and they provided information on 1369 fishing trips. Catch records were weighted, using the results of contemporaneous fishing activity and fleet size surveys, to provide yield estimates for each fishing ground ( qoliqoli ). Yield from all qoliqoli was dominated by Serranidae and Lethrinidae which were favoured for consumption and sale. Yields were expressed on the basis of reef area for fish from different trophic groups. Macroinvertebrate-feeders and piscivores accounted for more than half the yield in all qoliqoli and there were significant differences in area specific yield between qoliqoli. There was no evidence of fishers adopting more powerful fishing techniques or catching fish from lower trophic levels in order to maintain yield from any qoliqoli. This suggested that the fisheries examined were all capable of sustaining the reported yields of up to 3.4 tonne km⁻² qoliqoli year ⁻¹ or 10.2 tonne km⁻² coral reef year ⁻¹ and that in sites where yields were less they might be increased sustainably.     

Projected distributions of Southern Ocean albatrosses,petrels and fisheries as a consequence of climatic change

Given the major ongoing influence of environmental change on the oceans, there is a need to understand and predict the future distributions of marine species in order to plan appropriate mitigation to conserve vulnerable species and ecosystems. In this study we use tracking data from seven large seabird species of the Southern Ocean (black‐browed albatross Thalassarche melanophris, grey‐headed albatross T. chrysostoma, northern giant petrel Macronectes halli, southern giant petrel M. giganteus, Tristan albatross Diomedea dabbenena, wandering albatross D. exulans and white‐chinned petrel Procellaria aequinoctialis, and on fishing effort in two types of fisheries (characterised by low or high‐bycatch rates), to model the associations with environmental variables (bathymetry, chlorophyll‐a concentration, sea surface temperature and wind speed) through ensemble species distribution models. We then projected these distributions according to four climate change scenarios built by the Intergovernmental Panel for Climate Change for 2050 and 2100. The resulting projections were consistent across scenarios, indicating that there is a strong likelihood of poleward shifts in distribution of seabirds, and several range contractions (resulting from a shift in the northern, but no change in the southern limit of the range in four species). Current trends for southerly shifts in fisheries distributions are also set to continue under these climate change scenarios at least until 2100; some of these may reflect habitat loss for target species that are already over‐fished. It is of particular concern that a shift in the distribution of several highly threatened seabird species would increase their overlap with fisheries where there is a high‐bycatch risk. Under such scenarios, the associated shifts in distribution of seabirds and increases in bycatch risk will require much‐improved fisheries management in these sensitive areas to minimise impacts on populations in decline.     

Polymorphic microsatellite markers for stock identification in Japanese anchovy (Engraulis japonica)

Japanese anchovy (Engraulis japonica) is a migratory marine fish of high economic significance in Taiwan. The adult Japanese anchovies migrate from the East China sea to spawn in coastal waters of Taiwan; the larvae then drift back to the East China Sea to complete their life cycle. We developed six highly polymorphic microsatellites for E. Japonica (expected heterozygosity ranging from 0.751 to 0.971) and these microsatellites can be used as genetic markers for identifying stocks to establish regulations in fishing management. Moreover, the markers will be useful in inferring the stock origins and migration routes in the future.     

The intrinsic vulnerability to fishing of coral reef fishes and their differential recovery in fishery closures

Coral reef fishes differ in their intrinsic vulnerability to fishing and rates of population recovery after cessation of fishing. We reviewed life history-based predictions about the vulnerability of different groups of coral reef fish and examined the empirical evidence for different rates of population recovery inside no-take marine reserves to (1) determine if the empirical data agree with predictions about vulnerability and (2) show plausible scenarios of recovery within fully protected reserves and periodically-harvested fishery closures. In general, larger-bodied carnivorous reef fishes are predicted to be more vulnerable to fishing while smaller-bodied species lower in the food web (e.g., some herbivores) are predicted to be less vulnerable. However, this prediction does not always hold true because of the considerable diversity of life history strategies in reef fishes. Long-term trends in reef fish population recovery inside no-take reserves are consistent with broad predictions about vulnerability, suggesting that moderately to highly vulnerable species will require a significantly longer time (decades) to attain local carrying capacity than less vulnerable species. We recommend: (1) expanding age-based demographic studies of economically and ecologically important reef fishes to improve estimates of vulnerability; (2) long term (20–40 years), if not permanent, protection of no-take reserves to allow full population recovery and maximum biomass export; (3) strict compliance to no-take reserves to avoid considerable delays in recovery; (4) carefully controlling the timing and intensity of harvesting periodic closures to ensure long-term fishery benefits; (5) the use of periodically-harvested closures together with, rather than instead of, permanent no-take reserves.     

Predation on adult Atlantic salmon, Salmo salar L., by otters, Lutra lutra (L.), within the River Dee system, Aberdeenshire, Scotland

Predation on adult salmon, Salmo salur L., by otters, Lurra lutra (L.), varied seasonally on the R. Dee, Aberdeenshire, Scotland, being highest during the spawning season in winter. Predation is described for some tributaries of the river. Male fish were caught by otters more often than females, and it is suggested that they were most vulnerable during their extensive excursions up and down stream, particularly as they negotiated shallow riffles. Otters appeared to prey upon healthy fish rather than those infested with Saprolegnia sp. but there was no difference in the size, freshwater- or sea-age offish killed by otterscompared with 'kelts' which had died non-violently. At least some of the otters obtained most of their daily food requirements by catching a single salmon per night.
Considerable numbers of adult salmon may be killed by otters during the spawning period but it is suggested that, because most are males, this is unlikely to affect the breeding success of the salmon population. Most predation occurs outside the fishing season and so is unlikely to reduce the numbers of salmon caught by anglers.     

Dwindling food-fish species and fishers' preference: problems of conserving Lake Malawi's biodiversity

Most of Malawi's popular food-fish species are in decline. The fishers attribute this decline to overfishing, changes in climate, inadequate fishing technology and supernatural powers. Sedimentation of the lake and rivers due to poor agricultural practices, which can also be implicated in the demise of Malawi's fisheries, was not recognized by the fishers. This study tested and confirmed that the fishers would readily switch to exploiting ornamental fish (Mbuna) for subsistence and cash if the more favoured food-fish species continued to dwindle. However, as most of the Mbuna species are localized to specific rocky habitats and are endemic to certain parts of the lake, they may be vulnerable to overfishing. To safeguard Lake Malawi's rich fish species diversity: (i) alternative economic opportunities for the lakeshore people should be identified, evaluated and promoted to alleviate the fishing pressure, (ii) the Department of Fisheries should collaborate with local fishermen in promoting sustainable fish utilization, e.g., through public campaigns aimed at sensitizing fishermen on the status of the fisheries and the vulnerability of some fish communities to overfishing and environmental degradation, and (iii) the degree of Mbuna exploitation, now that the popular food fishes are in decline, should be monitored and, where necessary, regulated to promote sustainability.     

Rebound in functional distinctiveness following warming and reduced fishing in the North Sea

Functionally distinct species (i.e. species with unique trait combinations in the community) can support important ecological roles and contribute disproportionately to ecosystem functioning. Yet, how functionally distinct species have responded to recent climate change and human exploitation has been widely overlooked. Here, using ecological traits and long-term fish data in the North Sea, we identified functionally distinct and functionally common species, and evaluated their spatial and temporal dynamics in relation to environmental variables and fishing pressure. Functionally distinct species were characterized by late sexual maturity, few, large offspring, and high parental care, many being sharks and skates that play critical roles in structuring food webs. Both functionally distinct and functionally common species increased in abundance as ocean temperatures warmed and fishing pressure decreased over the last three decades; however, functionally distinct species increased throughout the North Sea, but primarily in southern North Sea where fishing was historically most intense, indicating a rebound following fleet decommissioning and reduced harvesting. Yet, some of the most functionally distinct species are currently listed as threatened by the IUCN and considered highly vulnerable to fishing pressure. Alarmingly these species have not rebounded. This work highlights the relevance and potential of integrating functional distinctiveness into ecosystem management and conservation prioritization.