Grenadiers of the World Oceans: Biology, Stock Assessment, and Fisheries

2008 ◽  
Keyword(s):  
Stock Assessment ◽  
Distribution Patterns ◽  
Abundant Species ◽  
Trawl Survey ◽  
Bathymetric Range ◽  
Main Species ◽  
The World ◽  
Species Specific ◽  
Depth Ranges ◽  
Preanal Length

<em>Abstract</em>.—The objective of this study is to describe the distribution patterns of abundance and biomass, on a geographic and bathymetric basis, of the main macrourid species of Mozambique waters. Catch data from a demersal trawl survey (<EM>MOZAMBIQUE 07</EM>) were analyzed. The survey covered the continental shelf and upper-middle slope from 17°00’S to 26°50’S and from 100–700 m depth. Fourteen macrourid species were collected from 200 m and deeper. The most abundant species and the highest in biomass were <em>Coelorinchus braueri</em>, <em>C. trunovi, C. denticulatus</em>, <em>Ventrifossa nasuta</em>, and <em>Malacocephalus laevis</em>. Only those five species were analyzed in detail. The occurrence and yields by geographic and bathymetric range of these main species seem to reveal the existence of some species-specific preference for determinate depth ranges and/or geographic areas. Preanal length-weight relationships were estimated for <em>C. braueri, C. trunovi, </em>and <em>V. nasuta</em>: <em>a</em>= 0.00071; 0.00020; 0.00080; <em>b</em>= 2.50; 2.80; 2.76 and <em>r</em><sup>2</sup>= 0.93; 0.97; 0.78, respectively.

Grenadiers of the World Oceans: Biology, Stock Assessment, and Fisheries

2008 ◽  
Keyword(s):  
Stock Assessment ◽  
Seasonal Pattern ◽  
Distribution Patterns ◽  
Abundant Species ◽  
Depth Range ◽  
Total Size ◽  
Bathymetric Range ◽  
Important Species ◽  
Mean Size ◽  
Species Specific

<em>Abstract.</em>—The principal aim of this study is to describe the distribution patterns of abundance and biomass, on a seasonal and bathymetric basis of the main macrourid species from the Spanish Gulf of Cadiz. The results from 23 bottom-trawl surveys carried out in the study area in spring and autumn of 1993–2006 were analyzed. The most abundant species captured were common Atlantic grenadier <em>Nezumia aequalis </em>and saddled grenadier <em>Coelorinchus coelorhincus. </em>In terms of biomass, softhead grenadier <em>Malacocephalus laevis </em>was the third most important species and bluntsnout grenadier <em>Nezumia sclerorhynchus </em>and glasshead grenadier <em>Hymenocephalus italicus </em>were the least abundant species. Of the five species caught in the surveys, only <em>N. aequalis</em>, <em>M. laevis </em>and <em>C. coelorhincus </em>were analyzed in detail; their yields expressed in number of individuals/h represented the higher values and showed higher yields in spring than in autumn, suggesting a seasonal pattern of abundance. However, <em>C. coelorhincus </em>did not show this pattern except between 1999 and 2004. <em>N. aequalis </em>showed the widest bathymetric range. The observed yields in the depth gradient for the three species revealed species-specific preferences for a determinate depth range. In relation to mean total size, larger individuals of <em>M. laevis </em>and <em>N. aequalis </em>were observed during the March surveys. <em>C. coelorhincus </em>was the only species that showed a slight increase in mean size with increasing depth.

Grenadiers of the World Oceans: Biology, Stock Assessment, and Fisheries

2008 ◽  
Keyword(s):  
Stock Assessment ◽  
Distribution Data ◽  
Depth Range ◽  
Multivariate Statistical ◽  
Data Set ◽  
Species Checklist ◽  
The World ◽  
Depth Ranges ◽  
The Vertical Distribution ◽  
Very High

<em>Abstract.</em>—Extensive trawling efforts off Taiwan, supplemented by collections from trawlers’ harvest at several local fishing harbors, have raised the total number of Taiwan’s grenadier fishes to 71 species in 18 genera and 3 families. Despite a relatively limited coastline (500 nautical miles), the species diversity in Taiwan is very high. The largest genus <em>Coelorinchus </em>(formerly known as <em>Caelorinchus</em>) is represented by 21 species, followed by <em>Ventrifossa </em>with 8, and <em>Nezumia </em>with 6. All other genera had five or fewer representatives. Five species were described based on specimens from Taiwan, and two of them, <em>Coelorinchus leptorhinus </em>and <em>C. sheni, </em>have not been reported elsewhere. A total of 33 species and 10 genera are newly recorded from Taiwan; these were collected only within the past two years. Because the maximum depth trawled only reached about 2,000 m in this study, it should be expected that more deeper-water grenadiers will be found in the future. Our depth-distribution data-set of collected specimens and depth ranges from 55 stations were insufficient to effectively separate the species into groups using multivariate statistical analysis. However, the factors influencing grenadier species composition in this study still can be recognized as per the following sequence: water depth, geographical region, and type of net. The vertical distribution of grenadiers in Taiwan appears to have a separation at 600 m and 1000 m. An annotated species checklist with ASIZP cataloged specimens documenting Taiwan distributions, and detailed collecting information, including body size, location, and depth range are provided.

Grenadiers of the World Oceans: Biology, Stock Assessment, and Fisheries

2008 ◽  
Keyword(s):  
Stock Assessment ◽  
Distribution Patterns ◽  
Common Species ◽  
Depth Range ◽  
The North ◽  
The World ◽  
Mid Atlantic Ridge ◽  
The North Atlantic ◽  
Species Composition And Distribution ◽  
Trawl Catches

<em>Abstract.—</em>The Mid-Atlantic Ridge of the North Atlantic is inhabited by at least 16 macrourid species in 9 genera. The species composition and distribution patterns are analysed based on bottom trawl catches in the depth range 985 to 3461m conducted on the 2004 MAR-ECO expedition between the Azores and the southern Reykjanes Ridge. Some of the species, e.g. roundnose grenadier <em>Coryphaenoides rupestris</em>, <em>C. brevibarbis </em>and abyssal grenadier <em>C. armatus, </em>rank among the most abundant demersal fishes on the ridge or in the deep axial valleys or fracture zones, while others are uncommon or rare. While a few species have apparently restricted northerly or southerly distributions, most are widespread. Among common species that occur along the entire ridge section investigated, there are indications of structuring by depth of occurrence.

assessing the status of demersal elasmobranchs in uk waters: a review

2005 ◽  
Vol 85 (5) ◽  
pp. 1025-1047 ◽  
Author(s):  
j.r. ellis ◽  
n.k. dulvy ◽  
s. jennings ◽  
m. parker-humphreys ◽  
s.i. rogers
Keyword(s):  
Life Histories ◽  
Stock Assessment ◽  
Length Distribution ◽  
Abundant Species ◽  
Biological Data ◽  
Life History Stages ◽  
Elasmobranch Fish ◽  
The Status ◽  
Over Exploitation ◽  
Species Specific

elasmobranch fish are susceptible to over-exploitation by commercial and recreational fisheries and an increasing focus of conservation initiatives. the lack of accurate species-specific landings data in many european fisheries and the paucity of biological data have restricted the types of stock assessment that can be undertaken. hence, other methods of determining the overall status of elasmobranch fish are required. for demersal elasmobranchs around the british isles, the most widely available biological data describe life histories and abundance from fishery-independent surveys. here, we examine the length-distribution of demersal elasmobranchs caught during groundfish surveys, to determine which life history stages are sampled effectively. for these stages, we report trends in abundance and relate the trends to knowledge of the species' biology and fisheries, and to the decline criteria that are used to assess species' status by nature conservation agencies. the analyses show that many large demersal elasmobranchs have been severely depleted in uk waters but that groundfish surveys still provide a good source of data for monitoring changes in status of the more abundant species. for rare and highly depleted species, groundfish surveys often provide good retrospective descriptions of declines, but the surveys have limited power to detect recent changes in status.

scholarly journals Recrutamento de animais sésseis e sedentários em substrato artificial na área portuária do Recife – PE, com enfoque para a bioinvasão

2021 ◽  
Vol 3 (4) ◽  
pp. 2307-2323
Author(s):  
Arthur V. O. M. Melo ◽  
Ralf Schwamborn ◽  
Cristiane M. R. Farrapeira
Keyword(s):  
Exotic Species ◽  
Ballast Water ◽  
Abundant Species ◽  
Benthic Species ◽  
Coverage Area ◽  
Main Species ◽  
Port Area ◽  
Metal Plates ◽  
Significant Difference ◽  
The World

RESUMO O Porto do Recife recebe uma grande quantidade de navios de vários tipos e de muitas partes do mundo, podendo trazer espécies exóticas incrustadas no casco ou em água de lastro. O objetivo do presente estudo foi registrar e analisar os padrões de recrutamento de espécies bentônicas sésseis, assim como investigar uma possivel introdução de espécies bentônicas exóticas e criptogênicas em uma área portuária com grande fluxo de navios. Utilizaram-se placas de metal galvanizado para estudo do recrutamento de animais sésseis e sedentários em três pontos amostrais no porto, com três réplicas cada, totalizando nove pontos, durante seis meses (outubro de 2010 a março de 2011), considerado como período seco. As placas de recrutamento foram retiradas a cada 30 dias durante seis meses. As principais espécies de acordo com a área de cobertura foram Mytella charruana (72%) e Amphibalanus improvisus (22%) e espaços vazios (7,5%). Não houve diferença significativa quando comparadas as três estações no porto do Recife, sendo encontradas diferenças quando comparadas os dados das áreas de cobertura das espécies mais abundantes no recrutamento. Foram elas: Clytia gracilis, Obelia dichotoma, M. charruana e A. improvisus.   ABSTRACT The Port of Recife receives a large number of vessels of various types and from many parts of the world, and can bring exotic species encrusted hull or in ballast water. The aim of this study was to record and analyze the patterns of recruitment of sessile benthic species, as well as investigating a possible introduction of exotic and cryptogenic benthic species in a port area with great flow vessels. We used galvanized metal plates to study the recruitment of sessile and sedentary animals at three stations in the harbor, with three replicas each, totaling nine points, six months (October 2010 to March 2011), considered the dry . The plates recruitment were taken every 30 days for six months. The main species according to coverage area were Mytella charruana (72%) and Amphibalanus improvisus (22%) and voids (7.5%). There was no significant difference when comparing the three stations in the Port of Recife, differences were found when comparing the coverage areas of most abundant species in recruitment. They were: Clytia gracilis, Obelia dichotoma, M. charruana and A. improvisus.  

Grenadiers of the World Oceans: Biology, Stock Assessment, and Fisheries

2008 ◽  
Keyword(s):  
Sex Ratio ◽  
Deep Sea ◽  
Stock Assessment ◽  
Geographical Range ◽  
Frequency Of Occurrence ◽  
Bathymetric Range ◽  
The World ◽  
General Frequency ◽  
Squat Lobsters ◽  
Crustacean Fisheries

<em>Abstract.</em>—Eight species of grenadiers are captured in the fisheries for the demersal squat lobsters <em>Cervimunida johni </em>and <em>Pleuroncodes monodon </em>and deep sea shrimp <em>Heterocarpus reedi </em>in northern and central Chilean waters (21°34–38°29S and 70–617 m depth)<em>: Coelorinchus aconcagua, C. chilensis, C. fasciatus, Coryphaenoides delsolari, Lucigadus nigromaculatus, Nezumia pulchella, Trachyrincus helolepis </em>and <em>T. villegai. </em>Several species were caught beyond their previously known geographical range in Chile, including <em>C. aconcagua </em>(north to 21°34’S), <em>N. pulchella </em>(south to 35°41’S), and <em>T. helolepis </em>(south to 38°29’S). In general, frequency of occurrence and size of the different species showed an increase with depth, suggesting that there may be larger size classes at depths greater than those of the crustacean fisheries. The sex ratio of several species changed with depth, showing that females and juveniles tend to occupy the entire bathymetric range analyzed, whereas males frequented deeper waters.

scholarly journals Responses of Bat Communities (Mammalia: Chiroptera) to Forest Loss and Habitat Conversion in Southern Cameroon

2021 ◽  
Vol 14 ◽  
pp. 194008292110103
Author(s):  
Patrick Jules Atagana ◽  
Eric Moïse Bakwo Fils ◽  
Sevilor Kekeunou
Keyword(s):  
Secondary Forest ◽  
Biosphere Reserve ◽  
Abundant Species ◽  
Primary Forest ◽  
Habitat Types ◽  
Habitat Transformation ◽  
Significant Difference ◽  
Southern Cameroon ◽  
Habitat Conversion ◽  
Species Specific

We aimed to assess how bats are affected by habitat transformation by comparing bat assemblages in four habitat types: primary forest, secondary forest, cocoa plantations and human habitations in the Dja Biosphere Reserve of southern Cameroon. Bats were sampled in the four habitat types using mist nets. During 126 nights, a total of 413 bats were captured, belonging to four families, 16 genera and 24 species. Ninety three individuals (17 species) were captured in the primary forest, followed by plantations (105 individuals, 14 species), human habitations (159 individuals, 10 species), and secondary forest (55 individuals, eight species). Megaloglossus woermanni was recorded in all the four habitats, and was the most abundant species (105 individuals). The analysis of bat assemblage between habitat types showed a statistically significant difference in species composition. The distribution of the six most abundant species ( Epomops franqueti, Megaloglossus woermanni, Rousettus aegyptiacus, Dohyrina cyclops, Hipposideros cf. caffer and Hipposideros cf. ruber) was influenced by habitat types. Our results suggest that the decrease in species richness observed in disturbed habitats may be due to habitat perturbations of primary forest habitats. Therefore, it is important to examine the effects of habitat conversion at species level, as responses are often species-specific.

Distribution patterns and population structure of Illex coindetii (Cephalopoda: Ommastrephidae) in the Southern Tyrrhenian Sea: Historical series of 14 years trawl survey

2011 ◽  
Vol 109 (2-3) ◽  
pp. 342-350 ◽  
Author(s):  
Anna Perdichizzi ◽  
Laura Pirrera ◽  
Daniela Giordano ◽  
Francesco Perdichizzi ◽  
Barbara Busalacchi ◽  
...  
Keyword(s):  
Population Structure ◽  
Distribution Patterns ◽  
Trawl Survey ◽  
Tyrrhenian Sea ◽  
Historical Series ◽  
Southern Tyrrhenian Sea

scholarly journals Correcting density-dependent effects in abundance estimates from bottom-trawl surveys

2014 ◽  
Vol 71 (5) ◽  
pp. 1107-1116 ◽  
Author(s):  
Stan Kotwicki ◽  
James N. Ianelli ◽  
André E. Punt
Keyword(s):  
Stock Assessment ◽  
Dead Zone ◽  
Walleye Pollock ◽  
Assessment Model ◽  
Bottom Trawl ◽  
Trawl Survey ◽  
Negative Consequences ◽  
Catch Per Unit Effort ◽  
Density Dependent ◽  
Index Of Abundance

Abstract Indices of abundance are important for estimating population trends in stock assessment and ideally should be based on fishery-independent surveys to avoid problems associated with the hyperstability of the commercial catch per unit effort (cpue) data. However, recent studies indicate that the efficiency of the survey bottom trawl (BT) for some species can be density-dependent, which could affect the reliability of survey-derived indices of abundance. A function qe∼f(u), where qe is the BT efficiency and u the catch rate, was derived using experimentally derived acoustic dead-zone correction and BT efficiency parameters obtained from combining a subset of BT catch data with synchronously collected acoustic data from walleye pollock (Theragra chalcogramma) in the eastern Bering Sea (EBS). We found that qe decreased with increasing BT catches resulting in hyperstability of the index of abundance derived from BT survey. Density-dependent qe resulted in spatially and temporarily variable bias in survey cpue and biased population age structure derived from survey data. We used the relationship qe∼f(u) to correct the EBS trawl survey index of abundance for density-dependence. We also obtained a variance–covariance matrix for a new index that accounted for sampling variability and the uncertainty associated with the qe. We found that incorporating estimates of the new index of abundance changed outputs from the walleye pollock stock assessment model. Although changes were minor, we advocate incorporating estimates of density-dependent qe into the walleye pollock stock assessment as a precautionary measure that should be undertaken to avoid negative consequences of the density-dependent qe.

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