Kittiwake breeding success in the southern North Sea correlates with prior sandeel fishing mortality

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Migratory connectivity and local site fidelity in red knots on the southern Pacific coast of South America

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Preferred foraging areas of Heard Island albatrosses during chick raising and implications for the management of incidental mortality in fisheries

• 1. Incidental mortality in fisheries is causing declines in many albatross populations around the world. To assess potential interactions with regional fisheries satellite tags were used to track black-browed albatrosses (Thalassarche melanophrys) and light-mantled sooty albatrosses (Phoebetria palpebrata) breeding on Heard Island during the chick-rearing periods of 2003/04. This was the first time individuals from either population had been tracked.
• 2. Black-browed albatrosses foraged largely within the Heard and McDonald Islands Economic Exclusion Zone (EEZ) north-east of the island, although 20% of foraging trips were to areas north of the EEZ into Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) areas 58.5.1 and 58.5.2 and into the Îles Kerguelen EEZ.
• 3. In contrast, the light-mantled sooty albatrosses foraged well south of Heard Island along the southern boundary of the Antarctic Circumpolar Current. Both species appear to face minimal risk of incidental mortality during the chick-rearing period in the regulated, legal fisheries, but are threatened by illegal, unreported and unregulated (IUU) fishing vessels operating in the southern Indian Ocean.

Copyright © 2007 John Wiley & Sons, Ltd.     

167 individuals versus millions of hooks: bycatch mitigation in longline fisheries underlies conservation of Amsterdam albatrosses

1. Industrial fisheries represent one of the most serious threats worldwide to seabird conservation. Death of birds in fishing operations (i.e. bycatch) has especially adverse effects on populations of albatrosses, which have extremely low fecundity. 2. The single population worldwide of Amsterdam albatross (Diomedea amsterdamensis) comprises only 167 individuals and risks considerable decline over the mid‐term from additional mortality levels potentially induced by fisheries. The priority actions listed in the current conservation plan for this species included characterizing the longline fisheries operating within its range, dynamically analysing the overlap between albatrosses and these fisheries, and providing fisheries management authorities with potential impact estimates of longline fisheries on the Amsterdam albatross. 3. During all life‐cycle stages and year quarters the birds overlapped extensively with fishing effort in the southern Indian and Atlantic oceans. Fishing effort, and consequently overlap score (calculated as the product of fishing effort and time spent by the birds in a spatial unit) was highest in July–September (45% of the hooks annually deployed). Just three fleets (Taiwanese, Japanese and Spanish) contributed to >98% of the overlap scores for each stage (72% from the Taiwanese fleet alone, on average). Daily overlap scores were higher for the non‐breeding versus the breeding stages (3‐fold factor on average). 4. Based on previous bycatch rates for other albatross species, this study estimated that longline fisheries currently have the potential to remove ~2–16 individuals (i.e. ~5%) each year from the total Amsterdam albatross population, depending on whether bycatch mitigation measures were or were not systematically employed during the fishing operations. 5. Recent bycatch mitigation measures may be instrumental in the conservation of the Amsterdam albatross. This study suggests three further key recommendations: (1) to focus conservation efforts on the austral winter; (2) to require all operating vessels to report ring recoveries; and (3) to allocate special regulation of fishing operations in the areas of peak bycatch risk for the Amsterdam albatrosses. Copyright © 2015 John Wiley & Sons, Ltd.     

Foraging areas of black‐browed and grey‐headed albatrosses breeding on Macquarie Island in relation to marine protected areas

• 1. Although marine protected areas (MPAs) are often established to protect threatened top‐order predators, there is a paucity of data that can be used to evaluate their efficacy in achieving this purpose.
• 2. We assessed the effectiveness of a network of MPAs around Macquarie Island in the Southern Ocean by examining the foraging areas of breeding black‐browed Thalassarche melanophrys and grey‐headed albatrosses T. chrysostoma.
• 3. During late incubation and brood periods over 90% of time spent foraging by black‐browed albatrosses was contained within MPAs, principally the Economic Exclusion Zone (EEZ) around Macquarie Island. In contrast, grey‐headed albatrosses spent only 34% of their time foraging in MPAs.
• 4. Black‐browed and grey‐headed albatrosses spent 30% and 15% of their respective foraging times in the Marine Park around Macquarie Island.
• 5. Both black‐browed and grey‐headed albatrosses foraged in Antarctic waters under the jurisdiction of the Convention for the Conservation of Antarctic Marine Living Resources (CCAMLR), accounting for 5% and 12% of the total foraging times respectively.
• 6. The spatial extent of MPAs around Macquarie Island appear to adequately cover much of the foraging distribution of breeding black‐browed albatrosses from Macquarie Island.
• 7. Breeding grey‐headed albatrosses spend significantly more time in waters outside the spatial extent of the surrounding MPAs and are at higher risk from fisheries activities and other threats.
• 8. Further information on the foraging movements both of albatrosses outside the breeding season and of juvenile albatrosses is required to more fully assess the efficacy of MPAs in protecting foraging habitats of these species.

Copyright © 2005 John Wiley & Sons, Ltd.     

Comparison of spatial distribution models to predict subtidal burying habitat of the forage fish Ammodytes personatus in the Strait of Georgia,British Columbia,Canada

1. The Pacific sand lance (Ammodytes personatus) is a key forage species for many commercially important fish (e.g. salmon and groundfish), marine birds, and whales found in nearshore coastal waters of British Columbia, Canada.
2. Sand lance lack a swim bladder and have a requirement for low-silt, medium-coarse sandy sea-bed habitat for burying. Little information is available describing the distribution of burying habitat, partly because there are no commercial fisheries for A. personatus in British Columbia.
3. This information is required by habitat and wildlife managers to identify and protect uncommon patches of burying habitats from detrimental activities, including dredging, infilling, and oil spills.
4. In this study, habitat distribution results from five suitability modelling algorithms were evaluated: maximum entropy, generalized linear model, generalized additive model, random forest, and an ensemble model of the latter three.
5. The maximum entropy model had the highest performance score (area under the receiver operator characteristic curve was 0.78) and was selected as the model that most accurately identified the presence of suitable A. personatus burying habitat.
6. Model results indicate that suitable burying habitat is primarily influenced by derived sea-bed substrate, distance to estuary, distance to sand-gravel beaches, and bottom sea temperature.
7. Overall, the spatial modelling identified only 105 km² of highly suitable sand lance burying habitat, or 2.6% of the study area (0–150 m), primarily in Haro Strait, along the east coast of Vancouver Island, and in northern regions of the strait near Cortes, Savary, and Harwood islands.
8. Identification of this uncommon and patchy burying habitat will contribute to the ongoing conservation of an important coastal prey species.

     

Morphometry and histology to assess the maturity stage of three endangered devil ray species (Elasmobranchii: Mobulidae) from the Gulf of California

1. Devil rays of the genus Mobula are subject to fishing exploitation worldwide and are considered vulnerable to overexploitation due to population reduction, which is evidenced by a decline in the number of catches of these animals.
2. Limited biological knowledge on these species has forced the use of precautionary conservation measures in countries where intensive fishing occurs.
3. This study aimed to describe biological data of interest for estimating the feasibility of the recovery of Mobula populations, emphasizing the reproductive activity of three endangered species of the genus Mobula (Mobula munkiana, Mobula thurstoni, and Mobula mobular) in the Gulf of California.
4. Reproductive organs were collected during 7 years of commercial fishing (2001–2007), and data on population structure, sex ratio, gamete production, and the number of offspring per breeding period were obtained.
5. Maturity stages were determined through histological analysis of the gonads for both sexes, and the size at maturity was estimated based on anatomical and histological characteristics of the specimens caught.
6. Considering the wide global distribution of Mobula species, there is an urgent need to apply strict conservation measures, such as established fishery closures during the breeding season or the establishment of catch periods after specimens have reached sexual maturity, especially in the countries where these animals are caught.

     

Genetic population structure of black‐browed and Campbell albatrosses,and implications for assigning provenance of birds killed in fisheries

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Identifying the origins of fishing gear ingested by seabirds: a novel multivariate approach

• 1. The global decline of albatrosses (Diomedidae: Procellariiformes) is thought to have occurred largely as a direct result of fishery‐related mortality. Albatrosses and other large petrels interact with fisheries in several ways, including scavenging used bait and discarded offal, which may contain hooks.
• 2. Hooks that are ingested by breeding birds are often fed to chicks which subsequently regurgitate them shortly before fledging.
• 3. In this study a series of mathematical (cladistic, cluster and principal components) analyses are applied to a sample of 241 items of fishing gear (hook, snood and hook/snood unit) collected from seabird nest sites on Bird Island, South Georgia, and 44 reference gear items provided by four South Atlantic regional fisheries.
• 4. The five separate analyses failed to assign most gear to a particular fishery or to identify any consistent annual trends. The homogeneous nature of the material, which was largely derived from the same manufacturers, meant that gear origin could not be determined. This suggests that hooks found at seabird colonies in this, and potentially other regions, will be of limited use in identifying offending fisheries, unless operators are obliged to deploy gear with unique marks in the future.
• 5. Nevertheless, it is suggested that this approach should work effectively where birds interact with a range of fisheries targeting different species using variable gear. This study therefore represents an innovative approach to the characterization of lost fishing gear with potentially widespread application. Copyright © 2010 John Wiley & Sons, Ltd.

     

Seabird interactions and by‐catch in the anchovy pelagic trawl fishery operating in northern Argentina

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Investigating seasonal habitat-use of saltwater crocodiles in the Ayeyarwady Delta to identify potential conservation areas in Myanmar

1. Understanding the impact of land-cover mosaics on crocodile distribution and habitat patterns is essential to prioritize areas for their conservation in human-dominated landscapes. This is especially important for species with specialist requirements; or where there is human–wildlife conflict, as is the case in many areas with crocodiles, such as Myanmar's Ayeyarwady Delta.
2. The saltwater crocodile is used as a surrogate species in this study to identify important conservation areas, and to propose potential protected areas for the Ayeyarwady coastal mangrove ecoregion. In total, 684 locations of saltwater crocodile encounters were collected, 444 for the wet season (May to June), and 240 for the dry season (December to January) between 1999 and 2018. Suitable habitats of saltwater crocodiles in the Ayeyarwady Delta were modelled for wet and dry seasons, using 12 predictor variables at 300-m resolution.
3. The area of suitable habitat in the wet season is about 1,272.3 km² but reduces to 563.7 km² in the dry season. Distance to the cropland, distance to the sea, mangrove cover, and wetland cover are identified as the key landscape variables that contributed to the seasonal habitat distribution of saltwater crocodiles in the Ayeyarwady Delta.
4. Protecting core and buffer areas in Kadonkani Reserved Forest and Pyindayae Reserved Forest would safeguard the seasonal habitats of saltwater crocodiles. Khaing Thaung Island, an unprotected area with suitable habitat areas for saltwater crocodiles, is proposed as a potential marine protected area in the Ayeyarwady Delta of Myanmar.

     

Río de la Plata voyagers: Deciphering the migration ecology of a vulnerable marine catfish (Genidens barbus) in a large subtropical river (lower Uruguay River)

1. Genidens barbus is a vulnerable marine migrant catfish with low fecundity, a complex life cycle (i.e. mouth breeding), and is the target of industrial and artisanal fisheries of several countries. This species regularly migrates from marine to freshwater environments of the south-western Atlantic.
2. The aim of this work was to delve deeper into the migration ecology of G. barbus, characterizing both its timing and potential environmental drivers. Furthermore, aspects of the population structure and reproduction of migrants in the lower Uruguay River were studied and the presence of juveniles in the adjacent estuarine recruitment area was evaluated.
3. Data from 11 years (2008–2018) of records of adult G. barbus captured by artisanal fisheries were used alongside relevant environmental variables that were recorded monthly. Reproductive biology (i.e. sex ratio, gonadosomatic index, fecundity, and oocyte size) was analysed for a period of 3 years (2016–2018). The juvenile abundance in the Río de la Plata estuary was evaluated seasonally.
4. A total of 935 adult individuals of G. barbus were captured, representing a total biomass of 3,123 kg. The migration timing was from early spring to early summer. The abundance of migrants strongly increased with river discharge, suggesting that this variable regulates the upriver migration. Furthermore, pre- and post-spawn females and males displaying mouth breeding were recorded during the study period, confirming G. barbus reproduction in the lower Uruguay River.
5. The results obtained suggest that G. barbus ascend to spawn in the freshwater environments upstream from the mouth of the Uruguay River. Then, adult males incubate and carry the embryos downstream, releasing juveniles in the Río de la Plata estuary.
6. This relevant information will help with the implementation of effective management polices (e.g. fishing restrictions during the reproductive period) for the presently unregulated fishery of this vulnerable species in the lower Uruguay River.

     

Interactions between seabirds and pelagic squid-jigging vessels in the south-west Atlantic

1. The waters of the Patagonian Shelf in the south-west Atlantic are nutrient rich, support large concentrations of wildlife, and are exploited by several fisheries, including the large Asian squid-jigging fishery. Although the squid-jigging fishery has previously been observed to have few problems with the accidental mortality of seabirds, the deliberate catch for consumption of seabirds by the crew has been identified as a possible issue.
2. Four cruises were made between Uruguay and the Falkland Islands during 2005–2006 to quantify the impact of jiggers on seabirds from indirect observation platforms. Monitoring included closely approaching 116 jigging vessels and boarding seven for inspection.
3. The use of non-jigging fishing gear, either for catching fish or seabirds, was observed at the stern of 33 vessels. Twelve seabird carcasses were observed floating close to vessels during 13 days of monitoring. Although the results recorded here are not sufficient to put a confident estimate on the magnitude of this mortality, the density of carcasses floating in the water among the jigging fleet indicated the potential significance of this problem.
4. The results were considered sufficiently concerning for the Falkland Islands Government to take preventative actions, including educational efforts, improving humanitarian conditions onboard vessels, introducing relevant legislation and licence conditions, and prosecuting intentional seabird take inside the Falkland Islands jurisdiction. This has resulted in the apparent elimination of these mortalities within Falkland waters since the late 2000s.
5. Nevertheless, it is likely that the same initial conditions exist for the crews of squid jiggers on vessels operating on the high seas, and so the possibility of the targeting of seabirds for consumption continues. Squid fisheries with substantial numbers of jiggers overlap with important foraging areas for a range of albatross and other species in high-seas areas such as the Patagonian Shelf, the Humboldt and Kuroshio currents, and the south-west Pacific Ocean. These areas of overlap may be important to investigate, especially in the foraging grounds of declining seabirds.

     

Artisanal fishing,dolphins, and interactive pinger: A study from a passive acoustic perspective

1. Dolphins interact with many types of fishing gear, causing damage to fishing activities and in some cases facing harm and becoming entangled as bycatch.
2. In this study, the behaviour of bottlenose dolphins during their interaction with set nets, equipped with and without interactive pingers, was investigated. Acoustic monitoring of the nets was conducted for a total of 56 hauls and 814.9 hr of recordings, from the 16 October to 13 November 2015, along the coast of Lampedusa island (Sicilian Channel, Italy, Mediterranean Sea).
3. The level of interaction between dolphins and the nets was evaluated considering the number of dolphin clicks grouped over time (single acoustic incursion on each net), the duration of every acoustic incursion, and the number of dolphin clicks per incursion. Moreover, the catch rate was measured as the number of fish per hour for each net.
4. Based on the recording time of dolphin clicks, the spatio-temporal development of the interaction with the nets located in different bays of the island was assessed.
5. The duration of the interaction between dolphins and nets significantly increased over the study period, with a concomitant reduction in catch rate. The interactive pinger showed efficacy in protecting the nets from dolphin depredation during the first period of 36 hauls and 11 fishing days (higher catch rates and lower incursion durations), whereas no differences were found in any interaction parameters between pinger and control nets in the second period (20 hauls and six fishing days).
6. Interactive pingers may be an effective, short-term (2–3 weeks) tool in deterring depredation by bottlenose dolphins in small-scale artisanal fisheries. Other mitigation approaches, such as gear modification, lessons learned through outreach, and passive acoustic monitoring of the nets, could improve the management of the interactions between fisheries and bottlenose dolphins.

     

Distribution and habitat characteristics of three sympatric cetacean species in the coastal waters of Matang,Perak, Peninsular Malaysia

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Use of marine sanctuaries by far-ranging predators: commuting flights to the California Current System by breeding Hawaiian albatrosses

Quantifying the dispersion and habitats of far‐ranging seabirds, turtles, and cetaceans is essential to assess whether zoning strategies can help protect upper‐trophic marine predators. In this paper, we focus on Black‐footed Albatross (Phoebastria nigripes) use of three US national marine sanctuaries off central California: Cordell Bank, Gulf of the Farallones, and Monterey Bay. We assessed the significance of these protected areas to albatrosses by: (i) documenting commuting flights between Hawaiian breeding sites and the California Current System (CCS); (ii) quantifying albatross dispersion patterns on the central California continental shelf and slope, and (iii) characterizing albatross habitats within sanctuary waters using concurrent satellite‐tracking data and vessel‐based sightings. Chick‐rearing albatrosses commuted from their colony on Tern Island, Hawaii (23.878°N, 166.288°W), to the CCS (34–48°N) and two of the eight satellite‐tracked birds entered the marine sanctuaries. Among the telemetry locations within sanctuary waters, two‐thirds (24 of 36) straddled the shelf break and slope (201–2000‐m depth), a pattern underscored by a concurrent vessel‐based survey in which 144 Black‐footed Albatrosses were sighted. This study illustrates the value of coordinated satellite telemetry and vessel‐based surveys to assess the distributions of protected species within existing marine protected areas. More specifically, our results underscore the importance of three central California marine sanctuaries to Hawaiian albatrosses breeding in subtropical waters, approximately 4500 km away.     

Incidental capture of leatherback sea turtles in fixed fishing gear off Atlantic Canada

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Ex situ growing out of early stages of wild seahorses: Envisioning conservation options for threatened populations

1. Rafting has been proposed as a dispersive mechanism for some species of seahorses. Juvenile Hippocampus patagonicus rafting on the sea surface have been reported. This life stage has high mortality in nature due to ecological and environmental factors usually affecting juvenile planktonic teleosts (e.g. predation).
2. In this study, 50 juvenile seahorses were captured while rafting at the beginning of the reproductive season (December). They were grown out under a standard protocol in a recirculating aquaculture system for 120 days until they reached maturity.
3. During this period, only three seahorses died (6%). Mature seahorses were 65 ± 7 mm average height and showed variable coloration and pigmentation pattern (n = 47; 94%).
4. The availability of juvenile seahorses during the reproductive season and their high survival performance ex situ highlight the feasibility of developing protocols in which juvenile seahorses serve as a novel source of broodstock.

     

Present distribution of common dolphin Delphinus delphis in French Mediterranean and adjacent waters as obtained from small boat surveys

1. Common dolphin distribution in the western Mediterranean is still poorly known, with the exception of the Alboran Sea. In French waters, the species occurrence is suspected to have strongly decreased during the 20th century.
2. Small boat dedicated surveys from 1988 to 2012 were undertaken to describe common dolphin distribution in five regions of French waters and three southern regions of the western basin. A total survey effort of 38,561 km resulted in sightings of 25 common dolphin groups in the western basin.
3. Common dolphins were rarely observed off the French continental coast, more frequently around Corsica, and were quite frequent in waters off western Sardinia. Their most favoured habitat was found to be in neritic or upper slope waters.
4. The analysis of stranding records suggested that common dolphins were more abundant in French inshore waters prior to 1980.
5. A major increase of pelagic fish landings occurred from the beginning of the 1960s in the western part of French waters. Local populations of common dolphins may have declined as a consequence of prey depletion.