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Cephalopod Fishery Management

DWhatley

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Aggregation based Cuttlefish fishery Geetha Sasikumar Sr. Scientist, Molluscan Fisheries Division

Cephalopods are actively sought in artisanal fisheries with highly selective gears and fishing techniques based on knowledge of their biology and behaviour (Reid et al., 2005). Such techniques use substrates for egg deposition or use live sexually mature females as lures for attracting males while targeting spawning cuttlefishes.

Benthic FADs in the form of basket traps has been the most popular cuttlefish fishing method since olden times (Watanuki and Kawamura, 1999). Basket traps were employed around Inland Sea in Japan, Atlantic coast in Europe and by countries around the Mediterranean Sea for cuttlefish. Most benthic trapping and potting is carried out in reefy areas, where fish and other animals are concentrated by the sheltered nature of the bottom, either for protection or for feeding purpose. Japanese fishermen have been using cuttlefish trap for Sepia esculenta as early as 1660’s. Full-scale trap fishery began in 1920’s, when fishermen noticed that the introduction of spawning substrates inside the traps facilitated the capture of cuttlefish. Trap fishing practices, which was popular in western Japan later spread to much wider areas including Korean Peninsula.
...
Though FADs can be an effective fisheries enhancement tool, there are few negative aspects in their deployment. In the current observation, the presence of only spawning individuals in FAD assemblages indicates that the cuttlefishes are attracted towards the submerged substratum for attaching the spawned eggs. In the process, the spawning individual aggregate and therefore increases their susceptibility to exploitation. Despite the fact that, fish aggregation may be highly adaptive, imparting several advantages to group members such as decreasing the risk of predation, increasing foraging efficiency and increasing reproductive success, such methods that are targeting spawners should be discouraged considering the long-term sustainability of the resource
 

DWhatley

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Discussion paper regarding assessment of squid in the BSAI & GOA
Joint Plan Team Meeting Olav Ormseth NMFS Alaska Fisheries Science Center, Seattle, WA September 2014 (PDF)

Overview
Assessment of squid in the BSAI and GOA areas was reviewed in May 2013 by the Council of
Independent Experts (CIE). The reviewers had a number of comments regarding Tier 6 management in
general and squid assessment in particular. Many of the concerns they raised are issues that have been
discussed repeatedly at the Plan Team and SSC level, but they also noted that the approach used for
making harvest recommendations should be consistent between the BSAI and GOA areas. This document
was prepared as a response to the CIE review and includes suggestions for alternatives to the current
assessments that would be consistent between the BSAI and GOA.
Brief history of squid catches and management
Recent assessments (Ormseth 2011, 2012) provide extensive detail regarding squid catch and
management history and the differences between the BSAI and GOA. In the BSAI, squid catch data begin
in 1977 with some large catches during the foreign and joint-venture that may indicate targeting (Table 1
and Figure 1). In the GOA, catch records begin in 1990 with little indication of directed fishing (Table 1
and Figure 1). Recent patterns of incidental catches are similar in both areas, with years of relatively low
catch interspersed with much higher than average catches. The 2014 catch of squid to date appears to be
well above the average of recent catches with 1,461 t taken in the BSAI as of 9/8/2014. This exceeds the
TAC of 310 t but remains well below the ABC of 1,907 t and the OFL of 2,624 t. The 2014 GOA catch
(57 t as of 9/8/2014) is well below the TAC of 1,148 t.
Management of squid also differs between the two areas. In the BSAI, squid have been managed as a
target or “in the fishery” stock since the NPFMC Tier system was adopted. Harvest recommendations are
made using the Tier 6 approach, with OFL equal to the average catch 1978-1995. In contrast, squid in the
GOA were managed as part of the Other Species complex until 2011 when the complex was split into 4
species groups. At that time, the SSC selected a Tier 6 approach for squid that specified an OFL equal to
the maximum catch during 1997-2007 because catch data from the earlier period were unavailable.
The abundance of squid in the BSAI and GOA is highly uncertain. Survey biomass estimates (Table 2)
have acceptable CVs but undoubtedly underestimate squid populations. Estimates from mass-balance
ecosystem models indicate that squid biomass may be two orders of magnitude higher (880,000 t in the
BSAI and 369,000 t in the GOA; Aydin et al. 2007) but these estimates are also highly uncertain. Survey
biomass estimates are higher in the GOA than in the BSAI (recent averages of 7,759 t and 4,932 t,
respectively), but this may be due in part to differences in survey design between the two areas. Relative
to the EBS shelf and slope surveys, the GOA trawl survey has a higher density of stations in deeper
waters and slope habitats where squid are more likely to be encountered. ...
 

DWhatley

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New ageing method boosts octopus research

@Tintenfisch - Have you tried the weighing method with other species yet?

Until now, the lack of an efficient method to age octopuses has hindered progress of octopus population studies.

Stephen C Leporati, formerly of the Department of Fisheries, says the previous method—named Stylet Increment Analysis (SIA)—was effective, although costly and time consuming.

“We cut a small cross-section out of the middle of the stylet [a small cartilage-type structure in the head of the octopus] and placed it under a microscope to see lots of tiny concentric rings, much like those in a tree,” says Mr Leporati.

“Each ring represents a day in the life of the octopus, and by counting all the lines you get an idea of how old the octopus was.”

In this study, the team first confirmed that stylets grow in daily increments, using calcine injections to visibly mark the stylets of captive octopi.

They then used SIA to count stylet increments in 251 wild-caught Octopus (cf) tetricus, weighing these stylets to discover a strong correlation between the number of stylet increments and stylet weight.

“This trend enabled us to weigh the stylets as a means of ageing the octopus, vastly expanding the prospective sample size and opening up the possibility of ageing octopus populations more accurately and comprehensively than was previously possible,” says Mr Leporati.

The team went on to estimate the age of 3280 octopi, only by weighing their stylets.

They found age was proportional to stylet weight for both males and females, with maximum ages for males and females being 677 days and 542 days respectively.
Octopus catch rates spike
The study was part of a larger Fisheries Research and Development Corporation (FRDC) project designed to investigate the spike in octopus catch rates.
“The primary goal of the overarching project was to determine sustainable harvest rates for the developmental octopus fishery,” says Mr Leporati.
“The ageing study was an integral component of this, so we could understand the influence different rates of fishing pressure may have on the population.”
The new method allowed scientists to age thousands of octopi over just two years, helping to assess the state of the octopus population in WA.
“The overall conclusion from the project was that current fishing pressure is not having a major impact and the WA octopus population is in very good health.”
 

DWhatley

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Target Strength Measurements of Live Golden Cuttlefish Sepia esculenta at 70 and 120 kHz

Dae-Jae Lee, David A. Demer 2014 (pdf)

Introduction
Golden cuttlefish Sepia esculenta is a commercially important cephalopod species in Korea. They are caught mainly during their spawning season, from May to June, when adults migrate from deep water to the littoral zone along the southwest coast of Korea. Assessment of their population biomass has relied entirely on landings data from commercial fisheries using gill-nets, hand-jigs, traps, set-nets, and trawls. However, each of these fishing methods select different portions of the population, potentially biasing the assessment. During 2011 to 2013, about 3,207 metric tons (mt) of cuttlefish were landed annually; and about 662 mt (~21%) of these were caught in inshore gill nets (KOSTAT, 2014). The increased demand for cuttlefish in Korea has motivated resource managers to consider alternative sources of information about the cuttlefish stock in the inshore and coastal fishing grounds (Lee et al., 1998; Watanuki and Kawamura, 1999).
Towards the development of a fishery-independent acoustic method for surveying cuttlefish, the magnitude and variability in its acoustic target strength (TS) must be evaluated. TS is an indicator of the size of an acoustic target, and is used to convert measurements of echo energy to estimates of fish abundance. It is broadly known that TS varies with acoustic frequency, and fish species, size, and swimbladder volume
 

DWhatley

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Shipowners request octopus ban extension Spain 2015

The Association of Smaller Scale Gear of Galicia (ASOAR-ARMEGA) has asked the Secretariat of Marine Affairs of the Xunta of Galicia for the octopus ban not to be implemented only for those operating with traps, but also for the trawling fleet and recreational fishers.

While Galicia is negotiating a new management plan for octopus, the Association has suggested that the Government should prohibit the capture of the cephalopod between 15 May and 3 August, 2015, the newspaper La Voz de Galicia informed.

This means that they propose that the ban should last 30 days and during the remaining 75 days a biological stoppage should be decreed.

The ban would be supported by the sector while the biological stoppage would be funded by the Administration.

While last year a slight recovery of the resource was observed, ASOAR-ARMEGA members are cautious about the future.

The proposed closure would be accompanied by a special plan against the illegal activity and poaching.

The owners of inshore vessels have also argued that during the closure period a real and full recovery plan should be developed.

Jose Luis Rodriguez, ASOAR-ARMEGA president, explains that the octopus reproduces quickly, but its life cycle takes about two or three years, so it is necessary to "give room for spawning and for the specimens to lay eggs as many times as possible," the newspaper Faro de Vigo reported.

"We do not want our request to be misunderstood. It does not mean to be paid for doing nothing, but during that time we are ready to work for the Xunta by performing regeneration tasks as well as shoreline cleanup and monitoring," adds Rodriguez.

On the other hand, Correo Gallego reported that during the first quarter of 2015 catches on the coast of Terras, between Caión (A Laracha) and Rianxo, fell 23 per cent over the same period in 2014.

In addition, at the markets of the zone, a total of 266,355 kg was auctioned in the first quarter of 2015, which is 23 per cent less than in 2014.

Shortages of octopus did not translate into a rise in prices, so that billing also dropped, by 25 per cent.

Between January and March revenues of approximately EUR 1.3 million was achieved at Terras markets compared to EUR 1.7 million in the first quarter of 2014, indicated Pesca de Galicia.
 

tonmo

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This:
Jose Luis Rodriguez, ASOAR-ARMEGA president, explains that the octopus reproduces quickly, but its life cycle takes about two or three years, so it is necessary to "give room for spawning and for the specimens to lay eggs as many times as possible," the newspaper Faro de Vigo reported.
 

DWhatley

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Photos: periodic closure of fishing grounds boosts octopuses and helps coastal communities
Shreya Dasgupta
June 17, 2015



For communities that depend on fishing for their livelihoods, fishing bans as a way to conserve marine life are not always popular. But some villages in southwest Madagascar seem to have hit upon a strategy to reap economic gains from bans.

Temporarily closing down portions of their octopus-fishing areas every year not only helps villages revive declining octopus populations, but also generates more income for fishermen and fisherwomen, according to a study published today in PLOS ONE.

Fishing for octopus — predominantly the reef octopus (Octopus cyanea) — is a major source of livelihood for coastal communities in southwestern Madagascar. The fishers, mostly women, catch octopuses on coral-reef flats during low tide. Until recently, this was just a means of catching supper, but in recent years they have begun selling the octopuses to commercial seafood companies for export to Southern Europe. As a result, overfishing has increased and catches have declined.

So in 2004, following discussions with the London-based conservation group Blue Ventures Conservation and several of its partners, the remote fishing village of Andavadoaka in southwest Madagascar closed off a part of its octopus fishing grounds for 7 months. The closure site was around a barrier island, located seven kilometers (4.3 miles) offshore. While fishers were barred from catching octopuses during the closure period, they could continue to fish other species at the site. Blue Ventures provided technical, financial, and logistical support for the project.

"After the closure, the fishers landed enormous octopuses," Alasdair Harris, a marine ecologist and executive director of Blue Ventures, told mongabay.com. "And the practice then quickly snowballed, and neighboring villages very quickly adopted the practice."

...
 

DWhatley

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Taxonomic Study of the Cephalopods, particularly the Teuthoidea (Squids) and Sepoidea (Cuttlefish) in the Waters around Sri Lanka N. M. P, I PERERA 1975 (pdf)

Introduction
THERE has been very little organized effort directed specifically for the exploitation of the Cephalopods on a commercial scale, and the incidental catches made by various fishing methods such as scoop-nets, Beach-seine and trawler nets have contributed to the production of this variety. Very recently, there has been a sudden increase in the interest for the exploitation of this group in view of the demand abroad and available export market. This has resulted in an urgent need for information on the distribution of co rmercial varieties of Cephalopods, and the development of efficient methods for exploiting them. In view of the fact that there is hardly any published information available about the Cephalopods in the waters around Sri Lanka, it has become necessary to undertake a preliminary taxonomic study of this group, before venturing into the more detail investigations of the resources of this group. In the course of this preliminary studies, the author was successful in identifying 8 species of Cephalopods falling into the orders Teuthoidea and Sepoidea. However this does not mean that this is a complete list.
 

DWhatley

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Spatially Explicit Modeling Reveals Cephalopod Distributions Match Contrasting Trophic Pathways in the Western Mediterranean Sea
Patricia Puerta,Mary E. Hunsicker,Antoni Quetglas,Diego Álvarez-Berastegui,Antonio Esteban,María González,Manuel Hidalgo 2015 (full paper)


Abstract
Populations of the same species can experience different responses to the environment throughout their distributional range as a result of spatial and temporal heterogeneity in habitat conditions. This highlights the importance of understanding the processes governing species distribution at local scales. However, research on species distribution often averages environmental covariates across large geographic areas, missing variability in population-environment interactions within geographically distinct regions. We used spatially explicit models to identify interactions between species and environmental, including chlorophyll a (Chla) and sea surface temperature (SST), and trophic (prey density) conditions, along with processes governing the distribution of two cephalopods with contrasting life-histories (octopus and squid) across the western Mediterranean Sea. This approach is relevant for cephalopods, since their population dynamics are especially sensitive to variations in habitat conditions and rarely stable in abundance and location. The regional distributions of the two cephalopod species matched two different trophic pathways present in the western Mediterranean Sea, associated with the Gulf of Lion upwelling and the Ebro river discharges respectively. The effects of the studied environmental and trophic conditions were spatially variant in both species, with usually stronger effects along their distributional boundaries. We identify areas where prey availability limited the abundance of cephalopod populations as well as contrasting effects of temperature in the warmest regions. Despite distributional patterns matching productive areas, a general negative effect of Chla on cephalopod densities suggests that competition pressure is common in the study area. Additionally, results highlight the importance of trophic interactions, beyond other common environmental factors, in shaping the distribution of cephalopod populations. Our study presents a valuable approach for understanding the spatially variant ecology of cephalopod populations, which is important for fisheries and ecosystem management.
 

DWhatley

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Reproductive traits of Octopus maya (Cephalopoda: Octopoda) with implications for fisheries management
Omar Hernando Avila-Poveda (Avila-Poveda OH), Noussithe Koueta, Francisco Benitez Villalobos, Josefina Santos-Valencia, C. Rosas 2016 (full article)

ABSTRACT
Octopus maya is the main species caught in Mexico. From September 2007 to June 2008, its sex
ratio, reproductive season, frequency of non-vitellogenic and vitellogenic oocytes, reproductive
indices, and size and weight at maturity, were evaluated. The monthly sex ratio was
significantly different from 1:1. The major reproductive season occurs during February to June (dry season) in Yucatan. May − June is the common reproductive season to both Yucatán and Campeche populations. Higher frequencies of vitellogenic oocytes (> 50%) were found from January-March and in May. From
five reproductive indices, only the macroscopic and microscopic maturity indices were the best descriptors of the reproductive season in females, whilst only the reproductive complex index was the best descriptor in males. The weight at sexual maturity (BW 50% ) was 335 g for females and 242 g for males. The size at sexual maturity (DML 50% ) was 12.58 cm for females and 7.42 cm for males. It is recommend revising the
minimum catch size by following these results. The reproductive traits here evaluated could contribute to the recently created Plan for Management of Octopus Fisheries, in particular action line no. 1.4, which refers to protection of females during breeding, and to their protection throughout the entire reproductive season
 

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