The mean trophic level of Uruguayan landings during the period 1990–2001

Milessi, Andrés C.; Arancibia, Hugo; Neira, Sergio Peña; Defeo, Omar

doi:10.1016/j.fishres.2005.02.002

Cited by 45 publications

(32 citation statements)

References 25 publications

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“…Pauly et al (2000a) also found major changes in the fi sh communities and landings to have occurred in the northeast Atlantic, where trophic level plunged from a peak of nearly 3.7 in 1965 to only 2.8 in 1997. The increase we found in the landings data, from 122 160 t in 2002 to 169 192 t in 2011 was slightly stronger than the increase recorded by Milessi et al (2005) for Uruguayan landings during the period 1990-2001. The increased total landings may be related in part to technical innovation and the development of new fi shing gear designs.…”

Section: Discussioncontrasting

confidence: 66%

Mean trophic level of coastal fisheries landings in the Persian Gulf (Hormuzgan Province), 2002–2011

Razzaghi

Mashjoor

Kamrani

2016

Chin. J. Ocean. Limnol.

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Fishing activities can alter the structure of marine food webs by the selective removal of some species. The changes in the marine food webs of the Hormuzgan waters of the Persian Gulf, Iran were assessed, based on estimates of the mean trophic index (MTI) and Fishing in Balance index (FiB), and on landing profi le of the exploited marine community (49 species) during the period, 2002-2011. The total landings ( Y t ) ( R =0.88, P <0.001) increased gradually while the Y t of carnivores has slightly declined, and the Y t of herbivores, detritivores and omnivores has increased. Consequently, the MTI signifi cantly decreased ( R =-0.69, P <0.05) at a rate of 0.11 during this decade. The MTI showed a decreasing trend, which indicates exploitation of marine resources. The FiB index also showed a downward trend and negative values from 2002 to 2009, which may be associated with unbalanced structure in the fi sheries, but an upward trend from 2009 to 2011. The time variation of the landing profi le showed two periods with signifi cant diff erences in their species composition ( R =0.88; P =0.005), and based on analysis of similarity, species have been identifi ed as discriminator species, namely Thunnus albacores and Benthosema pterotum . Results indicate that changes in MTI refl ected changes in the Hormuzgan landing structure. The examination of the MTI, FBI, and landing profi le (LP) temporal pattern suggests that the status of fi shery resources in Hormuzgan inshore waters is overexploited, and provides evidence of the probability that a fi shing down process is occurring in this area, and that this trend may continue in the long-term. Therefore, environmental fi sheries management and conservation programs should be prioritized for these valuable resources.

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Section: Discussioncontrasting

confidence: 66%

Mean trophic level of coastal fisheries landings in the Persian Gulf (Hormuzgan Province), 2002–2011

Razzaghi

Mashjoor

Kamrani

2016

Chin. J. Ocean. Limnol.

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“…1b), for Uruguayan and Chilean landings the largest catches were made when the species with the highest trophic levels were caught (Milessi et al, 2005;Arancibia and Neira, 2005) and the TLm values declined at rates of 0.28 and 0.175 (without horse mackerel) per decade respectively. For Portugal too, the landings TLm declined at a lower rate, 0.05 per decade (Baeta et al, 2009), which is quite different from the situation off Angola, where the TLm fluctuated over five decades (Fig.…”

Section: Discussionmentioning

confidence: 97%

Ecosystem structure and trophic analysis of Angolan fishery landings

Angelini

Vaz-Velho²

2010

Sci. Mar.

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SUMMARY: Information on the mean trophic level of fishery landings in Angola and the output from a preliminary Ecopath with Ecosim (EwE) model were used to examine the dynamics of the Angolan marine ecosystem. Results were compared with the nearby Namibian and South African ecosystems, which share some of the exploited fish populations. The results show that: (i) The mean trophic level of Angola's fish landings has not decreased over the years; (ii) There are significant correlations between the landings of Angola, Namibia and South Africa; (iii) The ecosystem attributes calculated by the EwE models for the three ecosystems were similar, and the main differences were related to the magnitude of flows and biomass; (iv) The similarity among ecosystem trends for Namibia, South Africa and Angola re-emphasizes the need to continue collaborative regional studies on the fish stocks and their ecosystems. To improve the Angolan model it is necessary to gain a better understanding of plankton dynamics because plankton are essential for Sardinella spp. An expanded analysis of the gut contents of the fish species occupying Angola's coastline is also necessary.

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“…The decadal differences in the landing profiles are likely to be associated with strong declines in all traditional fishery resources (i.e. M. furnieri, C. guatucupa, M. schmitti) as a result of the fishing down marine food webs process in the ArgentineaneUruguayan Common Fishing Zone (Milessi et al, 2005;Jaureguizar and Milessi, 2008). The main coastal fishery resource, M. furnieri, is targeted by different fisheries (artisanal, coastal and shelf) and the available information indicates that it is in a critical state Carozza, 2010), overexploited (Vasconcellos and Haimovichi, 2006), or fully exploited at a higher level than its biological potential (Carozza and Rey, 2010).…”

Section: Discussionmentioning

confidence: 99%