scholarly journals Spatial considerations for the Dakhla stock of Octopus vulgaris: indicators, patterns, and fisheries interactions

2007 ◽  
Vol 64 (9) ◽  
pp. 1820-1828 ◽  
Author(s):  
Abdelmalek Faraj ◽  
Nicolas Bez
Keyword(s):  
Spatial Patterns ◽  
Octopus Vulgaris ◽  
Target Species ◽  
Stock Biomass ◽  
Spawning Stock ◽  
Productive Area ◽  
The Common ◽  
Fisheries Interactions ◽  
Demersal Species ◽  
Trawl Surveys

Abstract Faraj, A., and Bez, N. 2007. Spatial considerations for the Dakhla stock of Octopus vulgaris: indicators, patterns, and fisheries interactions. – ICES Journal of Marine Science, 64: 1820–1828. The common octopus (Octopus vulgaris) is the target species of the cephalopod fishery that exploits two stocks, Dakhla and Cap Blanc, off southern Morocco (26°N 21°N), an area commonly referred to as the Saharan Bank. Octopusvulgaris is also one of the most abundant demersal species in this highly productive area, and plays a key role in the upwelling ecosystem. Spatial patterns of the main phases of the Octopus vulgaris life cycle of the Dakhla stock are described, using trawl surveys carried out twice a year from 1998 to 2003. Using geostatistics and spatial indicators, mature females and juveniles are analysed and mapped to characterize the main features of the spawning and recruitment phases. There are clear distinctions between the spatial patterns of the spawning and recruitment phases: juveniles are more coastal, less spatially dispersed, more anisotropically distributed, and more patchy. Our results suggest that the spatial pattern of the Octopus vulgaris Dakhla stock is different from that of the same species in other ecosystems such as the Mediterranean. GIS reveals that the spawning–stock biomass is globally more accessible to the industrial fleet than to the artisanal one, a finding contrary to contemporary thinking and with important resource management implications.

scholarly journals Pots as alternative and sustainable fishing gears in the Mediterranean Sea: an overview

2021 ◽  
Author(s):  
Andrea Petetta ◽  
Massimo Virgili ◽  
Stefano Guicciardi ◽  
Alessandro Lucchetti
Keyword(s):  
Mediterranean Sea ◽  
Early Stage ◽  
Spiny Lobster ◽  
Mesh Size ◽  
Octopus Vulgaris ◽  
Target Species ◽  
Factors Affecting ◽  
Fishing Gears ◽  
Pros And Cons ◽  
The Mediterranean

AbstractStock overexploitation, bycatch, discards and gear impacts on the environment are outstanding issues for Mediterranean fisheries. The adoption of alternative fishing gears is an appealing solution to ensure a more sustainable exploitation of resources. We discuss the pros and cons of pots as alternative gears by reviewing their main designs, spatial distribution and target species in the Mediterranean basin. We assessed the technical factors affecting the catch efficiency of the different pot designs for four target species: spiny lobster, Palinurus elephas; Norway lobster, Nephrops norvegicus; common octopus, Octopus vulgaris and pandalid shrimps, Plesionika spp. We found that pot volume is important to catch Octopus; mesh size to catch Nephrops and Plesionika; entrance surface to catch Octopus, Nephrops and Plesionika; pot shape/colour and entrance shape/position to catch Octopus and Plesionika; and bait type to catch Octopus and Nephrops. The literature review shows that pot fisheries have several considerable advantages over conventional gears, especially in terms of discards, bycatch, seabed impacts (particularly compared with bottom trawls and passive set nets), size and species selectivity, gear depredation, catch quality and gear cost, besides saving time and labour. Disadvantages hampering their wider diffusion include ghost fishing, a low catch of finfish species, the narrow range of species targeted by each pot design and the current early stage of research. These data make a clear case for using pots as alternative gears to traditional ones in the Mediterranean Sea in some areas and seasons to catch certain target species.

scholarly journals Seasonal population dynamics of Octopus vulgaris in the eastern Mediterranean

2006 ◽  
Vol 63 (1) ◽  
pp. 151-160 ◽  
Author(s):  
Stelios Katsanevakis ◽  
George Verriopoulos
Keyword(s):  
Eastern Mediterranean ◽  
Late Summer ◽  
Main Peak ◽  
Octopus Vulgaris ◽  
Late Winter ◽  
Visual Census ◽  
The Common ◽  
Specific Growth Rates ◽  
Seasonal Population ◽  
Seasonal Population Dynamics

Abstract The population density of Octopus vulgaris was measured by visual census with scuba diving in coastal areas in Greece (eastern Mediterranean). A time-variant, stage-classified, matrix population model was developed to interpret the seasonal variation of octopus stage densities and to estimate several life cycle parameters. An annual and a semi-annual periodic cycle were found in the stage densities. A main peak of benthic settlement was observed during summer and a secondary, irregular one during late autumn. Two spawning peaks were estimated, a main one during late winter–spring and a secondary one during late summer–early autumn. More than 50% of the just-settled individuals will eventually die after 3 months. Mortality rate declines, as individuals grow larger, reaches a minimum approximately 6 months after settlement, and then grows again probably because of terminal spawning. The life expectancy of recently settled individuals (<50 g) during their summer peak is approximately 5 months. The lifespan of the common octopus is estimated to be between 12 and 15 months. The octopuses' mean specific growth rates (±s.d.) in their natural environment were 1.61 ± 0.30 d−1 for 50–200 g individuals and 1.19 ± 0.31 d−1 for 200–500 g individuals.

scholarly journals A two-stage biomass model to assess the English Channel cuttlefish (Sepia officinalis L.) stock

2014 ◽  
Vol 71 (9) ◽  
pp. 2457-2468 ◽  
Author(s):  
Michaël Gras ◽  
Beatriz A. Roel ◽  
Franck Coppin ◽  
Eric Foucher ◽  
Jean-Paul Robin
Keyword(s):  
Reference Points ◽  
Sea Surface ◽  
Sepia Officinalis ◽  
Sustainable Utilization ◽  
English Channel ◽  
Two Stage ◽  
Stock Biomass ◽  
Exploitation Rate ◽  
Spawning Stock ◽  
Age Structured

Abstract The English Channel cuttlefish (Sepia officinalis) is the most abundant cephalopod resource in the Northeast Atlantic and one of the three most valuable resources for English Channel fishers. Depletion methods and age-structured models have been used to assess the stock, though they have shown limitations related to the model assumptions and data demand. A two-stage biomass model is, therefore, proposed here using, as input data, four abundance indices derived from survey and commercial trawl data collected by Ifremer and Cefas. The model suggests great interannual variability in abundance during the 17 years of the period considered and a decreasing trend in recent years. Model results suggest that recruitment strength is independent of spawning–stock biomass, but appears to be influenced by environmental conditions such as sea surface temperature at the start of the life cycle. Trends in exploitation rate do not reveal evidence of overexploitation. Reference points are proposed and suggestions for management of the sustainable utilization of cuttlefish in the English Channel are advanced.

Modelling the effects of establishing a marine reserve for mobile fish species

2002 ◽  
Vol 59 (3) ◽  
pp. 405-415 ◽  
Author(s):  
P Apostolaki ◽  
E J Milner-Gulland ◽  
M K McAllister ◽  
G P Kirkwood
Keyword(s):  
Fish Species ◽  
Marine Reserve ◽  
High Mobility ◽  
Merluccius Merluccius ◽  
Seasonal Movements ◽  
Stock Biomass ◽  
Spawning Stock ◽  
Short And Long Term ◽  
Immature Fish

We present a model of the effects of a marine reserve on spawning stock biomass (SSB) and short- and long-term yield for a size-structured species that exhibits seasonal movements. The model considers the effects of protecting nursery and (or) spawning grounds under a range of fishing mortalities and fish mobility rates. We consider two extremes of effort redistribution following reserve establishment and analyze the effects of a reserve when the fishery targets either mature or immature fish. We apply the model to the Mediterranean hake (Merluccius merluccius) and show that a marine reserve could be highly beneficial for this species. We demonstrate benefits from reserves not just for overexploited stocks of low-mobility species, but also (to a lesser extent) for underexploited stocks and high-mobility species. Greatly increased resilience to overfishing is also found in the majority of cases. We show that a reserve provides benefits additional to those obtained from simple effort control. Benefits from reserves depend to a major extent on the amount of effort redistribution following reserve establishment and on fishing selectivity; hence, these factors should be key components of any evaluation of reserve effectiveness.

scholarly journals Shotgun Proteomics Analysis of Saliva and Salivary Gland Tissue from the Common Octopus Octopus vulgaris

2018 ◽  
Vol 17 (11) ◽  
pp. 3866-3876 ◽  
Author(s):  
Legana C. H. W. Fingerhut ◽  
Jan M. Strugnell ◽  
Pierre Faou ◽  
Álvaro Roura Labiaga ◽  
Jia Zhang ◽  
...  
Keyword(s):  
Salivary Gland ◽  
Shotgun Proteomics ◽  
Octopus Vulgaris ◽  
Proteomics Analysis ◽  
Salivary Gland Tissue ◽  
Gland Tissue ◽  
The Common ◽  
Common Octopus

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.

Aquaculture potential of the common octopus (Octopus vulgaris Cuvier, 1797): a review

Aquaculture ◽  
2004 ◽  
Vol 238 (1-4) ◽  
pp. 221-238 ◽  
Author(s):  
Paulo Vaz-Pires ◽  
Pedro Seixas ◽  
Alexandra Barbosa
Keyword(s):  
Octopus Vulgaris ◽  
The Common ◽  
Common Octopus

scholarly journals Does predation by grey seals (Halichoerus grypus) affect Bothnian Sea herring stock estimates?

2012 ◽  
Vol 69 (8) ◽  
pp. 1448-1456 ◽  
Author(s):  
Anna Gårdmark ◽  
Örjan Östman ◽  
Anders Nielsen ◽  
Karl Lundström ◽  
Olle Karlsson ◽  
...  
Keyword(s):  
Marine Mammals ◽  
Halichoerus Grypus ◽  
Grey Seal ◽  
Older Individuals ◽  
Standard Assessment ◽  
Abundance Estimates ◽  
Stock Biomass ◽  
Key Species ◽  
Spawning Stock ◽  
Bothnian Sea

Abstract Gårdmark, A., Östman, Ö., Nielsen, A., Lundström K., Karlsson O., Pönni, J., and Aho, T. 2012. Does predation by grey seals (Halichoerus grypus) affect Bothnian Sea herring stock estimates? – ICES Journal of Marine Science, 69: . Mortality of small pelagic fish due to marine mammals is generally considered to be low compared with other sources of mortality. With recent recoveries of marine mammal predators worldwide, this may no longer hold. The grey seal (Halichoerus grypus) population in the Bothnian Sea has increased fivefold since 1985. Its main prey, herring (Clupea harrengus), is a key species for fisheries in the region. Yet, current stock assessments assume constant natural mortality, leading to a risk of biased stock estimates with increasing predation and misleading analyses of herring population dynamics. We estimated grey seal predation from diet data and reanalysed herring spawning stock biomass (SSB) during 1973–2009. Accounting for predation increased the herring SSB 16% (maximum 19%), but this was within the confidence intervals when ignoring predation. Although mortality in older individuals was inflated when accounting for seal predation, this did not change the conclusions about drivers of herring dynamics. Accounting for grey seal predation is important for abundance estimates of old herring, but currently not for SSB estimates, given the great uncertainties in the standard assessment. The grey seal impact on Bothnian Sea herring will need to be reassessed if stock age composition, grey seal feeding preferences, or total stock development change.

scholarly journals From injury to full repair: nerve regeneration and functional recovery in the common octopus,Octopus vulgaris

2019 ◽  
Author(s):  
Pamela Imperadore ◽  
Dario Parazzoli ◽  
Amanda Oldani ◽  
Michael Duebbert ◽  
Ansgar Büschges ◽  
...  
Keyword(s):  
Nerve Regeneration ◽  
Functional Recovery ◽  
Internal Control ◽  
Regenerative Process ◽  
Full Recovery ◽  
Complete Analysis ◽  
Octopus Vulgaris ◽  
Original Structure ◽  
The Common ◽  
Common Octopus

AbstractSpontaneous nerve regeneration in cephalopod molluscs occurs in a relative short time after injury, achieving functional recovery of the lost capacities. In particular, transection of the pallial nerve in the common octopus (Octopus vulgaris) determines loss and subsequent restoring of two functions fundamental for survival, i.e. breathing and skin patterning, the latter involved in communication between animals and concealing. The phenomena occurring after lesion have been investigated in a series of previous studies, but a complete analysis of the changes occurring at the level of the axons and the effects on animals appearance during the whole regenerative process is still missing. Our goal is to determine the course of events following injury. Our goal is to determine the course of events following injury, from impairment to full recovery.We observed nerve regeneration, end-target re-innervation and functional reconnections between central brain and periphery, using the contralateral nerve in the same animal as internal control. The final architecture of the regenerated nervous tissue does not mirror the original structure, however functionality returns to match the phenotype of an intact octopus, and with no visible impact on the behaviour of the animal. This provides exceptional value to these findings for future studies.Summary statementHere we report events occurring after interruption of the peripheral neural circuitry inOctopus vulgaris, from the dramatic loss of normal functioning to full recovery.

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