Surveys as a research tool for managing dynamic stocks

Pennington, Michael; Strømme, Tore

doi:10.1016/s0165-7836(98)00129-5

Cited by 56 publications

(34 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Research surveys constitute the main fisheriesindependent data source and contribute to the assessment and management of fish populations (Pennington and Stromme 1998). This study is based on data collected during the MEDIAS survey, which is of added value given that (1) the data lack spatial bias because the whole anchovy distribution area is covered and not only the fishing grounds; (2) catches are not restricted by depth or mesh size, so the entire population length range is sampled; (3) fisheries acoustics is a direct method based on "ground-truth" information, through which all the anchovy echotraces are identified (McClatchie et al 2000); and (4) the survey period coincides with the anchovy spawning peak (Giráldez andAbad 1995, Palomera 1992) and with the maximum anchovy abundance (Palomera and Sabatés 1990), so it is optimal for stock discrimination (Cadrin et al 2014).…”

Section: Discussionmentioning

confidence: 99%

“…Fishery-independent data provided by scientific surveys play an important role in the assessment and management of fish populations (Pennington and Stromme 1998). Research surveys are used to calibrate stock assessment models based on commercial catches (i.e.…”

Section: Introductionmentioning

confidence: 99%

“…fishery-dependent data) and to provide empirical, independent population checks. (Kline 1996, Pennington andStromme 1998). In order to determinate the anchovy spawning stock biomass, the small pelagic species assessment survey (MEDIAS) is carried out every summer by the countries within the European Union using acoustic methods.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Anchovy (Engraulis encrasicolus) otoliths reveal growth differences between two areas of the Spanish Mediterranean Sea

2017

View full text Add to dashboard Cite

Summary:Anchovy is a commercial species that supports large fisheries in the Mediterranean Sea. In addition, anchovy is an essential element of the pelagic food web, playing a considerable role in connecting the lower and upper trophic levels. Comparisons made regarding length frequency distribution, demographic structure, growth during the first year inferred from otoliths, and the condition factor of anchovy inhabiting the Spanish Mediterranean Sea (General Fisheries Commission for the Mediterranean management units, GSA06-Ebro Delta and 01-Alboran Sea), based on five-year data, clearly showed significant growth differences between areas and evidenced the existence of two independent anchovy stocks in the Spanish Mediterranean Sea. The anchovies inhabiting the Alboran Sea had higher growth than the anchovies inhabiting the Ebro Delta for the same age (one year old). The dramatic decline of the Alboran Sea anchovy could be related to the current management legislation in the Spanish Mediterranean Sea, based mainly on a common minimum catch size (9 cm), which should be revised given that sustainable anchovy exploitation is crucial for the pelagic food web equilibrium.Keywords: anchovy growth; length-frequency distribution; otolith first radius; anchovy stocks; condition factor; fisheries management; Spanish Mediterranean Sea. Otolitos de anchoa (Engraulis encrasicolus) revelan diferencias de crecimiento entre dos áreas del Mediterráneo españolResumen: La anchoa es una especie de interés comercial sometida a gran explotación pesquera en el mar Mediterráneo. Asimismo, esta especie es un elemento esencial de la cadena trófica pelágica dado que actúa como nexo entre los niveles más altos y más bajos de ésta. En este trabajo se han llevado a cabo comparaciones, basadas en un conjunto de datos de 5 años, entre las distribuciones de frecuencias de tallas; la estructura demográfica; el crecimiento durante el primer año, inferido empleando otolitos y el factor de condición de individuos de anchoa recogidos en el Mediterráneo español (unidades de gestión de la General Fisheries Commission for the Mediterranean, GSA06-Delta del Ebro y GSA01-Mar de Alborán), mostrando diferencias significativas entre áreas y evidenciando la existencia de dos stocks de anchoa independientes en el Mediterráneo español. Las anchoas procedentes del mar de Alborán presentaron un mayor crecimiento que aquellas procedentes del Delta de Ebro para la misma edad (1 año). La dramática disminución de la población de anchoa del mar de Alborán podría estar relacionada con la aplicación de una única legislación para todo el Mediterráneo español basada, principalmente, en una misma talla de primera captura (9 cm), que debería ser revisada puesto que la explotación sostenible de la anchoa es de crucial importancia para el equilibrio de la cadena trófica pelágica.Palabras clave: crecimiento de anchoa; distribución de frecuencias de tallas; primer radio del otolito; stocks de anchoa; factor de condición; gestión de pesquerías; mar Mediterráneo español.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Anchovy (Engraulis encrasicolus) otoliths reveal growth differences between two areas of the Spanish Mediterranean Sea

2017

View full text Add to dashboard Cite

show abstract

“…The objective of this paper was to carry out a preliminary analysis and comparison of different geographical areas from Gibraltar to the Aegean Sea by investigating the local distribution, abundance and population size structure of P. erythrinus, P. bogaraveo and P. acarne, on the continental shelf and upper and middle slope. Data collected by trawl surveys throughout the Mediterranean using the same methodology and gear (Bertrand et al, 2000(Bertrand et al, , 2002 represent a particularly suitable base for comparing abundance and length structure among several geographical regions and over time (Pennington and Strømme, 1998).…”

Section: Mediterranean Marine Demersal Resources: the Medits Internatmentioning

confidence: 99%

Geographical distribution, abundance and some population characteristics of the species of the genus Pagellus (Osteichthyes: Percirformes) in different areas of the Mediterranean

Spedicato

Greco

Sophronidis³

et al. 2002

Sci. Mar.

View full text Add to dashboard Cite

SUMMARY: The objective of this paper was to investigate the local distribution, abundance and population structure of Pagellus erythrinus, Pagellus bogaraveo and Pagellus acarne on the continental shelf and slope over a wide geographic area from Gibraltar to the Aegean Sea. The analysis was based on the data collected during six trawl surveys, from 1994 to 1999, carried out yearly in spring within the MEDITS EU project. P. acarne was mainly distributed on the continental shelf, with a relatively higher abundance in the western part of the Mediterranean basin, where the biomass indices of P. bogaraveo were also important on the continental slope. Throughout the studied area, P. erythrinus was mainly distributed on the continental shelf, with remarkable abundance indices in the eastern part of the Mediterranean and in Corsica's waters. Mean total lengths showed a highly significant decreasing trend from the western to the eastern geographical sectors.

show abstract

“…The accuracy of abundance estimates is obviously of central importance to fisheries management, but estimates based on CPUE data are problematic because standardized CPUE data do not account for increased efficiency in the fishing fleet or for spatial and temporal intensification (Pennington and Stromme 1998, Neis et al 1999b, Neis and Kean 2003. In addition, range contraction in remaining stocks may keep landings in mobile trawl fleets high, despite depletion (Hutchings 1996, Bennet 2008.…”

Section: Assessment and Management Approachesmentioning

confidence: 99%

Rebuilding the Namibian hake fishery: a case for collaboration between scientists and fishermen

Paterson¹,

Kainge²

2014

E&S

View full text Add to dashboard Cite

ABSTRACT. One of the most important fisheries in the northern Benguela is the Namibian hake fishery, which targets both Merluccius capensis and Merluccius paradoxus. In spite of attempts to rebuild the hake stocks that were severely depleted by distant-water fleets before Namibia's independence in 1990, stocks have failed to recover. Because the ecological goal of stock rebuilding competes with social and economic objectives on the political stage, the ability to make accurate abundance estimates is important. However, the precision of abundance estimates is impeded by lack of understanding of hake behavior and of the effects of environmental factors. Furthermore, at present both species of hake are assessed and managed as one Namibian stock. We present qualitative information derived from interviews that we conducted with Namibian hake trawl and longline fishers during the 2009 and 2010 fishing seasons, and information gleaned from analyzing logbook data. We contextualize both types of data within the scientific literature on Namibian hakes and the Namibian hake fishery. Fishers monitor sea surface and bottom temperature, water quality, currents, and weather, and they have detailed knowledge about the behavior and habitat of hakes. Fishers differentiate between three different types of M. capensis, which they associate with different fishing areas. They also describe innovations that have taken place over the past 20 years, which are of relevance to the assessment of fishing efficiency and effort, but have not been taken into account in the stock assessments. Our analysis of logbook data supports the increase in efficiency. The results show that closer collaboration between scientists and fishers has the potential to improve the accuracy of survey estimates and stock assessments, and thus is important for rebuilding of hake stocks and the hake fishery.

show abstract

Surveys as a research tool for managing dynamic stocks

Cited by 56 publications

References 16 publications

Anchovy (<em>Engraulis encrasicolus</em>) otoliths reveal growth differences between two areas of the Spanish Mediterranean Sea

Anchovy (<em>Engraulis encrasicolus</em>) otoliths reveal growth differences between two areas of the Spanish Mediterranean Sea

Geographical distribution, abundance and some population characteristics of the species of the genus <i>Pagellus</i> (Osteichthyes: Percirformes) in different areas of the Mediterranean

Rebuilding the Namibian hake fishery: a case for collaboration between scientists and fishermen

Contact Info

Product

Resources

About