Spatial patterns of distribution and relative abundance of coastal shark species in the Galapagos Marine Reserve

2018 ◽  
Vol 593 ◽  
pp. 73-95 ◽  
Author(s):  
D Acuña-Marrero ◽  
ANH Smith ◽  
P Salinas-de-León ◽  
ES Harvey ◽  
MDM Pawley ◽  
...  
Keyword(s):  
Spatial Patterns ◽  
Relative Abundance ◽  
Marine Reserve ◽  
Shark Species ◽  
Patterns Of Distribution ◽  
Galapagos Marine Reserve

scholarly journals Factors affecting relative abundance of low-mobility fishing resources: spiny lobster in the Galapagos Marine Reserve

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7278 ◽  
Author(s):  
Juan Carlos Murillo-Posada ◽  
Silvia Salas ◽  
Iván Velázquez-Abunader
Keyword(s):  
Monitoring System ◽  
Relative Abundance ◽  
Spatial Scales ◽  
Marine Reserve ◽  
Spiny Lobster ◽  
Fishing Effort ◽  
Additive Models ◽  
Catch Per Unit Effort ◽  
Monthly Basis ◽  
Galapagos Marine Reserve

Management of low-mobility or benthic fisheries is a difficult task because variation in the spatial distribution and population dynamics of the resources make the monitoring and assessment of these fisheries challenging. We assumed that environmental, spatial, and temporal factors can contribute to the variability of the relative abundance of such species; we used Generalized Additive Models for Location Scale and Shape (GAMLSS) to test this hypothesis using as a case study the lobster fishery (targeting two species) in the Galapagos Marine Reserve, Ecuador. We gathered data on each of the two species of lobster on a monthly basis over seven years, including: (a) onboard observers’ records of catch data, fishing effort, and ground location by trip, and (b) data from interviews undertaken with fishers at their arrival to port, recording the same type of information as obtained from onboard observers. We use this information to analyze the effect of the measured variables and to standardize the Catch per Unit Effort (CPUE) in each case, using the GAMLSS. For both species, the temperature, region, fishing schedule, month, distance, and the monitoring system were significant variables of the selected models associated with the variability of the catch rate. ForPanulirus penicillatus, CPUE was higher at night than during the day, and forPanulirus gracilisit was higher during the day. Increased temperature resulted in a decrease of CPUE values. It was evident that temporal, spatial scales and monitoring system can influence the variability of this indicator. We contend that the identification of drivers of change of relative abundance in low-mobility species can help to support the development of monitoring and assessment programs for this type of fisheries.

scholarly journals Feeding behavior and trophic interaction of three shark species in the Galapagos Marine Reserve

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4818 ◽  
Author(s):  
Diego Páez-Rosas ◽  
Paul Insuasti-Zarate ◽  
Marjorie Riofrío-Lazo ◽  
Felipe Galván-Magaña
Keyword(s):  
Feeding Behavior ◽  
Trophic Level ◽  
Marine Reserve ◽  
Trophic Niche ◽  
Tropical Pacific ◽  
The Other ◽  
Biological Knowledge ◽  
Shark Species ◽  
Galapagos Marine Reserve ◽  
The Tropical Pacific

There is great concern about the future of sharks in Ecuador because of the lack of biological knowledge of most species that inhabit the region. This paper analyzes the feeding behavior of the pelagic thresher shark (Alopias pelagicus), the blue shark (Prionace glauca) and the silky shark (Carcharhinus falciformis) through the use of stable isotopes of carbon and nitrogen (δ13C and δ15N), with the aim of determining the degree of interaction between these species in the Galapagos Marine Reserve. No interspecific differences were found in use of oceanic vs. inshore feeding areas (δ13C: Kruskal–Wallis test, p = 0.09). The position in the hierarchy of the food web where A. pelagicus feeds differed from that of the other species (δ15N: Kruskal–Wallis test, p = 0.01). There were no significant differences in δ13C and δ15N values between males and females of the three species (Student’s t-test, p > 0.05), which suggests that both sexes have a similar feeding behavior. A specialist strategy was observed in P. glauca (trophic niche breadth TNB = 0.69), while the other species were found to be generalist (A. pelagicus TNB = 1.50 and C. falciformis TNB = 1.09). The estimated trophic level (TL) varied between the three species. C. falciformis occupied the highest trophic level (TL = 4.4), making it a quaternary predator in the region. The results of this study coincide with the identified behavior in these predators in other areas of the tropical Pacific (Colombia and Mexico), and suggest a pelagic foraging strategy with differential consumption of prey between the three species. These ecological aspects can provide timely information when implementing in conservation measures for these shark species in the Tropical Pacific and Galapagos Marine Reserve.

scholarly journals International fisheries threaten globally endangered sharks in the Eastern Tropical Pacific Ocean: the case of the Fu Yuan Yu Leng 999 reefer vessel seized within the Galápagos Marine Reserve

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Elisa Bonaccorso ◽  
Nicté Ordóñez-Garza ◽  
Diana A. Pazmiño ◽  
Alex Hearn ◽  
Diego Páez-Rosas ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Marine Reserve ◽  
Tropical Pacific ◽  
Shark Species ◽  
Tropical Pacific Ocean ◽  
Population Declines ◽  
Eastern Tropical Pacific ◽  
International Conventions ◽  
Galapagos Marine Reserve

AbstractShark fishing, driven by the fin trade, is the primary cause of global shark population declines. Here, we present a case study that exemplifies how industrial fisheries are likely depleting shark populations in the Eastern Tropical Pacific Ocean. In August 2017, the vessel Fu Yuan Yu Leng 999, of Chinese flag, was detained while crossing through the Galápagos Marine Reserve without authorization. This vessel contained 7639 sharks, representing one of the largest seizures recorded to date. Based on a sample of 929 individuals (12%), we found 12 shark species: 9 considered as Vulnerable or higher risk by the IUCN and 8 listed in CITES. Four species showed a higher proportion of immature than mature individuals, whereas size-distribution hints that at least some of the fishing ships associated with the operation may have been using purse-seine gear fishing equipment, which, for some species, goes against international conventions. Our data expose the magnitude of the threat that fishing industries and illegal trade represent to sharks in the Eastern Tropical Pacific Ocean.

scholarly journals Temporal and spatial patterns on serra, Scomberomorus brasiliensis (Teleostei, Scombridae), catches from the fisheries on the Maranhão coast, Brazil

2001 ◽  
Vol 61 (4) ◽  
pp. 541-546 ◽  
Author(s):  
V. da BATISTA ◽  
N. N. FABRÉ
Keyword(s):  
Spatial Patterns ◽  
Relative Abundance ◽  
West Coast ◽  
The West ◽  
Temporal And Spatial Patterns ◽  
Eastern Brazil ◽  
North Eastern ◽  
Displacement Pattern ◽  
Temporal And Spatial ◽  
Demersal Species

The displacement pattern of the serra, Scomberomorus brasiliensis, in North-eastern Brazil was analyzed from landing data recorded from the fleet fishing serra. Serra fishery has two seasons: from September to February (demersal species plus serra), and from March to August (almost only large amounts of serra). S. brasiliensis relative abundance increases similarly along the coast from March, but decreases first on the West coast from June. Records indicate that serra is near the coast at least until September/October in Eastern grounds. From October to March (strongest spawning season) there is no record of shoals on the coast. We concluded that the Maranhão coast is just a part of the migration circuit of S. brasiliensis that may exceed 300 nautical miles.

Are boat strikes a threat to sea turtles in the Galapagos Marine Reserve?

2013 ◽  
Vol 80 ◽  
pp. 29-35 ◽  
Author(s):  
Judith Denkinger ◽  
Macarena Parra ◽  
Juan Pablo Muñoz ◽  
Constanza Carrasco ◽  
Juan Carlos Murillo ◽  
...  
Keyword(s):  
Sea Turtles ◽  
Marine Reserve ◽  
Galapagos Marine Reserve
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