Long-term changes in the diversity, abundance and size composition of deep sea demersal teleosts from the Azores assessed through surveys and commercial landings

2019 ◽  
Vol 32 ◽  
pp. 25 ◽  
Author(s):  
Régis V.S. Santos ◽  
Wendell M.M.L. Silva ◽  
Ana M. Novoa-Pabon ◽  
Hélder M. Silva ◽  
Mario R. Pinho
Keyword(s):  
Deep Sea ◽  
Linear Models ◽  
Fork Length ◽  
Size Composition ◽  
Demersal Fish ◽  
Scientific Data ◽  
Marine Habitat ◽  
Important Species ◽  
Commercially Important

To obtain important baseline information about population dynamics and to provide valuable insights about the possible effects of artisanal fishing on the demersal fish community, this study had three specific objectives: (1) to update the annotated list of demersal teleost species occurring in the Azores (mid-North Atlantic); (2) to describe their depth distribution and related fishery information; and (3) to evaluate annual changes in their observed abundance and length composition. To do this, a time series with about 25 years of scientific data from the commercial fishery and surveys was analyzed. The demersal teleost community was represented by 213 species, predominantly deep-water species, reflecting the main marine habitat in the Azores region. Fishery takes place mainly in the intermediate strata (200–600 m), where the most commercially important species occur. No changing in the fork length (LF) distribution toward small individuals caused by size-selective fishing was detected in this study. The high variability observed in the LF data indicates the need for more accurate studies considering alternative statistical analyses (e.g., generalised linear models) to examine the possible factors (e.g. depth coverage, gear configuration, soak time, and fishing area) that cause this variability. On the other hand, the abundance indices of some commercially important species appear to have declined (Phycis phycis, Pontinus kuhlii, Conger conger, Beryx splendens and B. decadactylus), while others appear to be more stable (Helicolenus dactylopterus) or even increasing (Mora moro). Although the available data are insufficient for a formal assessment on the status of exploited populations, the long-term analysis of commercial landings and survey data was used as a basis to assess deep sea demersal teleost fisheries of the Azores, under a precautionary approach.

scholarly journals Contributions to Management Strategies in the NE Atlantic Regarding the Life History and Population Structure of a Key Deep-Sea Fish (Mora moro)

Biology ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 522
Author(s):  
Régis Santos ◽  
Wendell Medeiros-Leal ◽  
Osman Crespo ◽  
Ana Novoa-Pabon ◽  
Mário Pinho
Keyword(s):  
Population Structure ◽  
Life History ◽  
Deep Sea ◽  
Management Strategies ◽  
Size Composition ◽  
Large Size ◽  
The Common ◽  
Fishing Impacts ◽  
Sea Fish

With the commercial fishery expansion to deeper waters, some vulnerable deep-sea species have been increasingly captured. To reduce the fishing impacts on these species, exploitation and management must be based on detailed and precise information about their biology. The common mora Mora moro has become the main deep-sea species caught by longliners in the Northeast Atlantic at depths between 600 and 1200 m. In the Azores, landings have more than doubled from the early 2000s to recent years. Despite its growing importance, its life history and population structure are poorly understood, and the current stock status has not been assessed. To better determine its distribution, biology, and long-term changes in abundance and size composition, this study analyzed a fishery-dependent and survey time series from the Azores. M. moro was found on mud and rock bottoms at depths below 300 m. A larger–deeper trend was observed, and females were larger and more abundant than males. The reproductive season took place from August to February. Abundance indices and mean sizes in the catch were marked by changes in fishing fleet operational behavior. M. moro is considered vulnerable to overfishing because it exhibits a long life span, a large size, slow growth, and a low natural mortality.

Biology and Management of Dogfish Sharks

2009 ◽  
Keyword(s):  
Stable Isotope ◽  
Isotope Composition ◽  
Feeding Habits ◽  
Important Species ◽  
Isotopic Signatures ◽  
Ecological Changes ◽  
Varied Diet ◽  
Commercially Important ◽  
C And N

Abstract.—Spiny dogfish <em>Squalus acanthias </em>are an abundant and commercially important species of fish off both the Atlantic and Pacific coasts of North America. They are opportunistic feeders and have a varied diet that can include many fish species, especially small forage fish such as herring, capelin, and sand lance as well as crustaceans, worms, euphausiids, gelatinous zooplankton, and cephalopods. The purpose of our present study is to investigate the utility of the second dorsal spine in providing multiyear information on the feeding habits of dogfish using stable isotope (C and N) analysis. The outer dentine and enamel layers of a spine from three dogfish (caught off the coast of British Columbia) were analyzed to obtain their stable nitrogen and carbon isotope composition (δ<sup>15</sup>N and δ<sup>13</sup>C, respectively). Each sample had annuli from multiple years, allowing possible seasonal migrations to be averaged over samples. The δ<sup>15</sup>N ranged from a low of 11.6‰ to a high of 14.9‰ over the three spines and δ<sup>13</sup>C ranged from –11.5‰ to –18.4‰. The variable isotopic signatures along the spine indicate that the method may be used to assess ecological changes. Stable isotope measurements of dogfish spines could be a valuable means of determining long-term changes in habitat usage and feeding ecology.

A holistic vision for our future deep ocean

2020 ◽  
pp. 201-206
Author(s):  
Eva Ramirez-Llodra ◽  
Maria Baker ◽  
Paul Tyler
Keyword(s):  
Deep Sea ◽  
Natural Capital ◽  
Synergistic Effects ◽  
Deep Ocean ◽  
Scientific Data ◽  
National Jurisdiction ◽  
Industrial Solutions ◽  
Sound Management ◽  
Holistic Vision

Healthy oceans are essential to maintain a healthy planet, but the ocean is facing many challenges that need urgent attention. Robust scientific data and innovative technological, policy, and industrial solutions are essential to support sound management of the deep-ocean natural capital, both within and beyond national jurisdiction, to ensure future healthy and productive oceans. As with many systems on Earth, there is a delicate ecological balance in the deep ocean that must be maintained. Understanding the interactions of the different components of natural capital in the deep sea is complex, as many of the variables are interlinked and many have cumulative and synergistic effects on the ecosystem. Add to this the global and changing effects of climate change and ocean acidification, and legislators and managers have a tough job ahead to account for all of these issues when designing appropriate conservation measures. It is important that scientists work hand in hand with multiple stakeholders to identify issues and research needs that contribute to enhancing knowledge and the science needed for decision-making to help towards securing a healthy future for our deep-ocean ecosystems and their long-term natural capital.

Coral reef gastropods - a sustainable resource?

1995 ◽  
Vol 2 (2) ◽  
pp. 142 ◽  
Author(s):  
Ann L. Poulsen
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Management Strategies ◽  
Local Extinction ◽  
Pacific Region ◽  
Vulnerable Species ◽  
Important Species ◽  
Commercially Important ◽  
Ornamental Species

Large, colourful coral reef gastropods including the Giant Triton Charonia tritonis,helmet shells (Cassidae), cowries (Cypraeidae) and volutes (Volutidae) are exploited in an unregulated and unsustainable way throughout much of the Indo-Pacific region. The consequences for their populations, for the populations of their prey or for the ecology of their habitats are rarely considered. Serious decline in stocks of edible coral reef molluscs through unregulated harvesting demonstrates the need for controls on the collection and trade of commercially important species. Continued, unrestricted collecting will eventually lead to the local extinction of vulnerable species on substantial numbers of reefs. Research on the biology and ecology of ornamental species is urgently needed to facilitate the implementation of appropriate management strategies for long-term utilization. A co-operative effort to monitor and regulate trade will also contribute toward the maintenance of sustainable gastropod populations on coral reefs.

Abundance of demersal fish resources in the Persian Gulf and Oman Sea

2006 ◽  
Vol 86 (6) ◽  
pp. 1455-1462 ◽  
Author(s):  
T. Valinassab ◽  
R. Daryanabard ◽  
R. Dehghani ◽  
G.J. Pierce
Keyword(s):  
Persian Gulf ◽  
Central Area ◽  
Demersal Fish ◽  
Total Biomass ◽  
Trawl Survey ◽  
Important Species ◽  
Fish Resources ◽  
Oman Sea ◽  
Commercially Important ◽  
The Persian Gulf

We report on results of a trawl survey during 2003–2004 to assess the abundance of demersal fish resources in the Persian Gulf and Oman Sea. Samples were taken at a total of 316 trawl stations selected following a stratified random procedure. Catch rates (catch per unit area, CPUA) and total biomass were estimated. Total demersal fish biomass was estimated to be approximately 73,000 tonnes in Persian Gulf waters and approximately 39,000 tonnes in the Oman Sea. The lowest CPUA was recorded in the west of the study area (stratum A, approximately 1700 kg/n.m.2) and the highest in the east (stratum Q, 13943.4 kg/n.m.2), although density of commercially important species was higher in the central area (stratum K). Catch rate and biomass varied significantly in relation to seabed depth. Commercially important demersal species made up around 60% of the estimated total biomass. The most abundant species groups were rays, catfish, grunts, nemipterids and carangids. Several important species (e.g. silver pomfret, croakers and sharks) appear to have declined since the late 1970s while others, such as rays and catfish, have increased.

scholarly journals Fisheries monitoring in Babel: fish ethnotaxonomy in a hotspot of common names

2013 ◽  
Vol 11 (2) ◽  
pp. 467-476 ◽  
Author(s):  
Marilia Previero ◽  
Carolina V. Minte-Vera ◽  
Rodrigo Leao de Moura
Keyword(s):  
Monitoring Program ◽  
Biological Species ◽  
Northeastern Brazil ◽  
Small Scale ◽  
Artisanal Fisheries ◽  
Important Species ◽  
Management Framework ◽  
Commercially Important ◽  
Fisheries Statistics

The lack of a long term, comprehensive and reliable fisheries statistics system is a major impediment to fisheries management in Brazil. Fishing is one of the main activities throughout the country's coast, with predominance of small-scale, artisanal, multigear, and multispecies captures that are landed in a pulverized network of coastal villages. Brazil is also a hotspot of common names, another feature that challenges artisanal fisheries' monitoring. We combined taxonomic and ethnobiological information to support the implementation of an artisanal fisheries' monitoring program under the co-management framework of a Marine Extractive Reserve in Bahia State, Northeastern Brazil. We surveyed 141 fishing landings, recording 86 fish species (43 families) and 52 correspondences 1:1 between local and scientific names. Broad folk categories had an average of 5.1 specific names, with "cação" (shark) being the category with more specific names (24 names to six biological species). With the exception of species that make up the bycatch captured by shrimp trawling, fisherfolks are able to identify commercially important species from both fresh specimens and photos. Common names can be reliably used in fisheries monitoring programs, and their usage facilitates the participation of fisherfolks in surveys based on voluntary or compulsory declarations of captures

scholarly journals Microplastic pollution of commercial fishes from coastal and offshore waters, Japan

2021 ◽  
Author(s):  
Mitsuharu Yagi ◽  
Tsunefumi Kobayashi ◽  
Yutaka Maruyama ◽  
Sota Hoshina ◽  
Satoshi Masumi ◽  
...  
Keyword(s):  
East China Sea ◽  
Marine Environment ◽  
Deep Sea ◽  
Demersal Fish ◽  
Pelagic Fish ◽  
Polymer Composition ◽  
Species Variation ◽  
Habitat Depth ◽  
Commercially Important ◽  
Demersal Species

Microplastics (MPs) pollution is a worldwide issue in the marine environment. There is growing concern of consuming MPs through fish, yet the current contamination status of fish collected from the deep sea surrounding Japan remains limited. We present baseline data on MPs in commercially important fishes from the coastal and offshore waters near Kyushu, Japan (East China Sea). We examined the MPs in the digestive tracts of two pelagic (n = 150 in total) and five demersal species (n = 235 in total). The fish were caught by pole and line, and bottom trawl at different geographical positions. The MPs in pelagic fish (39.1 %) were higher than demersal fish (10.3 %) and of larger sizes. The MPs correlated with habitat depth and type. There was species variation in the shape and polymer composition of MPs. These results increase our understanding of the heterogeneous uptake of MPs by fishes.

scholarly journals Persistent and substantial impacts of the Deepwater Horizon oil spill on deep-sea megafauna

2019 ◽  
Vol 6 (8) ◽  
pp. 191164 ◽  
Author(s):  
Craig R. McClain ◽  
Clifton Nunnally ◽  
Mark C. Benfield
Keyword(s):  
Oil Spill ◽  
Deep Sea ◽  
Deep Ocean ◽  
Deepwater Horizon ◽  
Important Species ◽  
Environmental Disasters ◽  
Coastal Impacts ◽  
Pelagic Food Webs ◽  
Commercially Important ◽  
Taxonomic Groups

The Deepwater Horizon spill is one of the largest environmental disasters with extensive impacts on the economic and ecological health of the Gulf of Mexico. Surface oil and coastal impacts received considerable attention, but the far larger oil spill in the deep ocean and its effects received considerably less examination. Based on 2017 ROV surveys within 500 m of the wellhead, we provide evidence of continued impacts on diversity, abundance and health of deep-sea megafauna. At locations proximal to the wellhead, megafaunal communities are more homogeneous than in unimpacted areas, lacking many taxonomic groups, and driven by high densities of arthropods. Degraded hydrocarbons at the site may be attracting arthropods. The scope of impacts may extend beyond the impacted sites with the potential for impacts to pelagic food webs and commercially important species. Overall, deep-sea ecosystem health, 7 years post spill, is recovering slowly and lingering effects may be extreme.

Potential impacts of non-native channel catfish on commercially important species in a Japanese lake, as inferred from long-term monitoring data

2011 ◽  
Vol 21 (4) ◽  
pp. 348-357 ◽  
Author(s):  
Shin-Ichiro S. Matsuzaki ◽  
Noriko Takamura ◽  
Kazunori Arayama ◽  
Atsushi Tominaga ◽  
Jun Iwasaki ◽  
...  
Keyword(s):  
Channel Catfish ◽  
Monitoring Data ◽  
Important Species ◽  
Commercially Important ◽  
Long Term Monitoring ◽  
Term Monitoring

Vertical Migration by Demersal Fish in the Northwest Atlantic

1966 ◽  
Vol 23 (1) ◽  
pp. 109-139 ◽  
Author(s):  
F. W. H. Beamish
Keyword(s):  
Seasonal Changes ◽  
General Pattern ◽  
Size Composition ◽  
Demersal Fish ◽  
Large Fish ◽  
Diurnal Difference ◽  
Commercially Important ◽  
Nova Scotian ◽  
Demersal Species ◽  
Trawl Catches

Observations on vertical patterns of migration were made on the Nova Scotian and Gulf of St. Lawrence fishing banks. The commercially important demersal species, cod, haddock, and redfish, were usually closely associated with bottom by day and moved off after dark. While this is the general pattern, variations occurred. Thus, on cloudy or dull days, redfish may remain in mid water. Cod did not always return to the seabed by day. Haddock, usually more closely associated with bottom than the other species, sometimes moved considerable distances from the seabed. Generally, concentrations of fish on bottom by day dispersed in mid water.In accord with vertical patterns of migration, bottom trawl catches were generally the lower by night. There was some suggestion of seasonal changes in the relation between day and night catches of cod and haddock. A suggestion of diurnal variation in size composition was found for haddock and yellowtail. More small haddock were taken by day than by night. Catches of large haddock tended to be the larger at night. Small yellowtail were the more abundant in night tows. No significant diurnal difference was found for large fish.

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