scholarly journals Vaquita: beleaguered porpoise of the Gulf of California, México

Therya ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 187-206
Author(s):  
Bernd Würsig ◽  
Thomas A. Jefferson ◽  
Gregory K. Silber ◽  
Randall S. Wells
Keyword(s):  
Gulf Of California ◽  
Line Transect ◽  
Human Consumption ◽  
External Appearance ◽  
Modern Times ◽  
Additional Information ◽  
Illegal Fishing ◽  
Acoustic Arrays ◽  
Totoaba Macdonaldi ◽  
Occurrence Patterns

The vaquita (Phocoena sinus), an endemic porpoise of the Gulf of California, México, was first described scientifically in 1958, from three skulls.  It is considered a sister taxon of an ancestor of the Southern Hemisphere Burmeister’s porpoise (P. spinipinnis) and spectacled porpoise (P. dioptrica), a case of antitropical distribution and speciation.  Vaquita in modern times seem to have existed largely in waters 10 to 30 m deep of the very northern Gulf of California, and may have already existed in relatively low numbers by the 1950s and 1960s.  The external appearance of the vaquita was not described until the late 1970s, and not until the 1980s and 1990s did additional information  about ecology and biology emerge.  Those studies and more recent shipboard and aerial visual line transect surveys, as well as stationary and boat-towed acoustic arrays, mapped occurrence patterns and approximate numbers in greater detail than before.  The first credible estimates of abundance appeared in the 1990s, with numbers in the mid-hundreds and declining.  While several reasons for the decline were originally postulated, mortality due to entanglement in nets has been established as the only known cause of decline, especially due to bycatch in large-mesh gillnets set for the endangered croaker fish totoaba (Totoaba macdonaldi).  This fish is prized in China for human consumption of its swim bladder, generally ground up for purported therapeutic purposes.  An extensive, lucrative fishery for totoaba, now illegal for many decades, has existed since at least the 1920s, and has recently increased.  Although there have been laudable attempts to stem or halt totoaba fishing, these have largely been unsuccessful, and as of this writing the vaquita is on the brink of extinction.  However, rapid concentrated action against illegal fishing with gillnets may yet save the species, and hope (with attendant action) must be kept alive.  This overview is followed by an appendix of a previously unpublished popular essay by K.S. Norris describing when, where, and how he first discovered the species, and subsequent early work relative to this newly-described porpoise.

scholarly journals Influence of sex and maturity state on trace elements content in liver and muscle of the SciaenidaeTotoaba macdonaldi

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11068
Author(s):  
Lia C. Méndez-Rodríguez ◽  
Berenice Hernández-Aguilar ◽  
Juan A. de Anda-Montañez ◽  
Eduardo F. Balart ◽  
Martha J. Román-Rodríguez ◽  
...  
Keyword(s):  
Trace Elements ◽  
Gulf Of California ◽  
Linear Models ◽  
Human Consumption ◽  
Fish Length ◽  
Maturity Stage ◽  
Dietary Reference Intake ◽  
Total Fish ◽  
Totoaba Macdonaldi ◽  
Migratory Movements

BackgroundThe fishTotoaba macdonaldiis endemic to the Upper Gulf of California. Its migratory movements involve sites with high levels of trace elements in the environment that can accumulate in tissues. In this study, lead (Pb), copper (Cu), cadmium (Cd), zinc (Zn) and iron (Fe) concentrations in male and female totoaba liver and muscle were quantified at various sexual maturity stages along the species’ geographic distribution.MethodsGeneralized linear models were used to explore associations between trace element concentrations and season of the year, sex/maturity stage, and total fish length.ResultsNo detectable Pb concentrations were recorded in liver or muscle; Cu, Cd, Zn and Fe contents in totoaba liver and muscle were typical of fish inhabiting areas with no contamination issues and are within international maximum permissible levels for human consumption. Variations in the content of Cd, Cu, Zn and Fe in liver of totoaba seem to be more related to the feeding and reproductive physiology of this species than as result of environmental exposure. Results suggest that consumption of totoaba muscle does not pose a public health risk. Furthermore, depending on the sex/maturity stage of totoaba, this fish’s muscle may provide approximately 70% Cu, 60% Zn and 100% Fe of the recommended dietary reference intake.

scholarly journals Cadmium, Lead, Copper, Zinc, and Iron Concentration Patterns in Three Marine Fish Species from Two Different Mining Sites inside the Gulf of California, Mexico

2021 ◽  
Vol 18 (2) ◽  
pp. 844
Author(s):  
Elisa Serviere-Zaragoza ◽  
Salvador E. Lluch-Cota ◽  
Alejandra Mazariegos-Villarreal ◽  
Eduardo F. Balart ◽  
Hugo Valencia-Valdez ◽  
...  
Keyword(s):  
Fish Species ◽  
Gulf Of California ◽  
Anthropogenic Activities ◽  
Iron Concentration ◽  
Dry Weight ◽  
Human Consumption ◽  
Metal Concentrations ◽  
Mining Sites ◽  
Copper Zinc ◽  
Cadmium Lead

In the Gulf of California; mineral deposits have contributed to high metal contents in coastal environments. This study examined cadmium; lead; copper; zinc; and iron contents in three fish species; Kyphosus vaigiensis (herbivore), Stegastes rectifraenum (omnivore), and Balistes polylepis (carnivore) at two mining sites. Metal concentrations were analyzed by atomic absorption spectrophotometry and stable nitrogen and carbon isotopes were estimated using mass spectrophotometry. Also, we assessed the risk to human health from the consumption of these three species based on permissible limits; although only two of them (Kyphosus and Balistes) are consumed as food. Metal concentrations differed among fish species; except for iron. The highest concentrations of metals were not always recorded in the species at the highest trophic level; i.e., Balistes. The highest concentrations (dry weight) recorded were cadmium (0.21 ± 0.03 µg g−1) and lead (1.67 ± 0.26 µg g−1), in S. rectifraenum; copper (1.60 ± 0.49 µg g−1) and zinc (67.30 ± 8.79 µg g−1), in B. polylepis; and iron (27.06 ± 2.58 µg g−1), in K. vaigiensis. Our findings show that each element accumulates differently in particular marine organisms; depending on the physiology of the species and the biogeochemistry of its habitat; which in turn is affected by the anthropogenic activities in adjacent areas. No risk of heavy metals toxicity is expected from the human consumption of the species and sites studied

scholarly journals Assessment and Valuation of Commercially Important Bivalves and Gastropods within the Seagrass Beds of Laguindingan, Misamis Oriental and Rizal, Zamboanga del Norte, Philippines

2021 ◽  
Vol 6 ◽  
Author(s):  
Joshua Zalsos ◽  
◽  
Dan Arriesgado ◽  
Elgen Arriesgado ◽  
Rodrigo Acuña
Keyword(s):  
Diversity Index ◽  
Organic Load ◽  
Line Transect ◽  
Human Consumption ◽  
Seagrass Beds ◽  
Monetary Value ◽  
Disturbed Area ◽  
Undisturbed Site ◽  
Commercially Important ◽  
Disturbed Site

A study was conducted to assess the abundance and value of commercially important bivalves and gastropods within the seagrass beds of Laguindingan, Misamis Oriental and Rizal, Zamboanga del Norte, Mindanao, Philippines. The line transect method was used to assess the diversity of the bivalves and gastropods within the seagrass beds and coring was used in collecting sediment samples. Laguindingan was categorized as undisturbed site, while Rizal as disturbed site. The results identified three families of gastropods in undisturbed and thirteen families in disturbed, comprising a total of seven bivalves and six gastropods. Cyprea sp. Dominated in undisturbed area, while Anadara inequivalves dominated in disturbed area. The diversity index in disturbed (1.57) was greater than in undisturbed (0.88) probably due to high organic matter (2.56ppm) compared to the undisturbed area (1.92ppm). Ironically, the total volume of bivalves and gastropods production in disturbed area was higher at19.84 kg compared with2.23 kg in undisturbed. In terms of total monetary value, the undisturbed production could yield PHP 22,672.32 (USD 466.48) in an approximated area of 165 ha, while PHP 422,130.50 (USD 8,685.37) in 326 ha in the disturbed area. The study revealed that higher diversity resulted in higher production with greater monetary value derived from bivalves and gastropods in disturbed area contributed by higher organic load. Protection and management of the seagrass beds is likely most needed in both disturbed and undisturbed are as to support not only a robust but also a healthy production of shellfish fit for human consumption.

scholarly journals Nutritional content of Totoaba macdonaldi (Gilbert, 1890), Antioxidants and lipid peroxidation in muscle

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11129
Author(s):  
Priscila Conde-Guerrero ◽  
Lia C. Méndez-Rodríguez ◽  
Juan A. de Anda-Montañez ◽  
Tania Zenteno-Savín
Keyword(s):  
Oxidative Stress ◽  
Lipid Peroxidation ◽  
Gulf Of California ◽  
Temporal Variations ◽  
Antioxidant Enzyme Activities ◽  
Stress Indicators ◽  
Sea Temperature ◽  
The North ◽  
Totoaba Macdonaldi ◽  
Oxidative Stress Indicators

Background Totoaba, Totoaba macdonaldi, is an endemic species of the Gulf of California, where wide variations in sea temperature throughout the year, surface salinities that gradually increase towards the north, and contamination by discharge of wastewater have been recorded. In addition to the challenges of reproduction and swimming, its characteristic biannual migration presents totoaba with changes in environmental factors that could affect oxidative stress indicators. The objective of this study was to assess spatial and seasonal changes in the oxidative stress indicators in muscle samples of totoaba. Methods Reactive oxygen species production, antioxidant enzyme activities and lipid peroxidation levels were quantified by spectrophotometry. Results Results suggest spatial-temporal variations of the oxidative stress indicators in muscle of totoaba that may be associated to a complex interaction between environmental and biological factors, including reproduction and nutrient availability. These results contribute to explain the appeal of totoaba as a marketable meat and suggest totoaba may provide antioxidant nutrients to consumers.

scholarly journals Viability of the vaquita, Phocoena sinus (Cetacea: Phocoenidae) population, threatened by poaching of Totoaba macdonaldi (Perciformes: Sciaenidae)

2021 ◽  
Vol 69 (2) ◽  
Author(s):  
Miguel A. Cisneros-Mata ◽  
Juan A. Delgado ◽  
Demetrio Rodríguez-Félix
Keyword(s):  
Gulf Of California ◽  
Population Viability Analysis ◽  
Policy Recommendations ◽  
Demographic Stochasticity ◽  
Term Survival ◽  
Factors Affecting ◽  
Viability Analysis ◽  
Age Structured ◽  
Totoaba Macdonaldi

Introduction: Despite extensive science-based conservation policy recommendations, with fewer than 20 individuals remaining, the vaquita (Phocoena sinus) -endemic to the Gulf of California- is the world’s most endangered marine mammal due to incidental catch in fishing nets and whether it can recover is unclear. Objective: Assess expectations for vaquita over the next two decades. Methods: We identified factors affecting the vaquita, constructed life tables, derived demographic parameters for different scenarios and conducted a population viability analysis using stochastic age-structured matrix Leslie models. Results: Analytical results indicate that the vaquita net growth rate is particularly sensitive to juvenile survival. We find that intensive, ongoing bycatch in gillnets used to poach totoaba (Totoaba macdonaldi) over the past decade brought the vaquita population to its current critically low size. Currently this seems to be exacerbated by demographic stochasticity and a potential Allee effect. Conclusions: If totoaba poaching is eliminated immediately, demographically, vaquita can recover; its long-term survival will depend on its uncertain genetic status, although a recent study found encouraging results in this regard.

scholarly journals How to increase demand for carp? Consumer attitudes and preferences in Germany and Poland

2020 ◽  
Vol 122 (11) ◽  
pp. 3267-3282 ◽  
Author(s):  
Katrin Zander ◽  
Yvonne Feucht
Keyword(s):  
Online Survey ◽  
Consumer Preferences ◽  
Protein Source ◽  
Human Consumption ◽  
Content Type ◽  
Point Of Sale ◽  
Additional Information ◽  
Market Shares ◽  
Off Flavors ◽  
Protein Supply

PurposeCarp is a traditional aquaculture fish with decreasing relevance in European markets. Despite this, it is a protein source which could contribute to the worldwide protein supply. Traditional carp ponds are part of human cultural heritage with high relevance for biodiversity. But, market shares of carp are small compared to other seafood market, mainly due to low consumer demand. The aim of this research was to contribute to the discussion on how to increase demand for carp by testing the acceptance of selected preprocessed carp products.Design/methodology/approachA quantitative online survey was conducted in Germany and Poland with the aim of identifying consumers' attitudes towards carp and carp products. On this basis recommendations on how to best market carp products are developed.FindingsCarp is perceived to be a fish eaten primarily at Christmas and New Year's Eve and to be difficult to prepare. The analyses reveal that a potential for novel carp products does exist in Germany and in Poland. The wider introduction of a bonecut filet to the market, a better availability of carp products, and the avoidance of off-flavors are important prerequisites for higher market relevance of carp.Research limitations/implicationsIn this research consumer preferences were elicited “theoretically” by showing pictures of carp products and asking them for their preferences. In this regard, the results presented here state a general consumer interest and a potential for new carp products. Further research, integrating product tastings might give additional information on the likely success of new types of carp products.Practical implicationsIn order to let people know about the new products and at the same time to combat the sometimes existent bad image of carp, product tastings, also in combination with information regarding local origin and environmental/cultural impact, should be offered at the point of sale.Originality/valueCarp is a highly sustainable fish and offers a valuable protein source for human consumption. But, in its common ways of market presentation it is not highly appreciated by consumers. This paper demonstrates options of overcoming this situation.

scholarly journals Vaquita Face Extinction from Bycatch. Comment on Manjarrez-Bringas, N. et al., Lessons for Sustainable Development: Marine Mammal Conservation Policies and Its Social and Economic Effects. Sustainability 2018, 10, 2185

2019 ◽  
Vol 11 (7) ◽  
pp. 2161 ◽  
Author(s):  
Karl Flessa ◽  
Luis Calderon-Aguilera ◽  
Carlos Cintra-Buenrostro ◽  
David Dettman ◽  
Gregory Dietl ◽  
...  
Keyword(s):  
Sustainable Development ◽  
Marine Mammal ◽  
Gulf Of California ◽  
River Flow ◽  
Economic Effects ◽  
Conservation Policies ◽  
Illegal Fishing ◽  
Ecological Changes ◽  
Mammal Conservation ◽  
Fishing Practices

We are among the scientists who have documented the environmental and ecological changes to the Upper Gulf of California following the reduction in the Colorado River’s flow. We object to any suggestion that our research supports Manjarrez-Bringas et al.’s conclusion that the decline in the Colorado River’s flow is the reason for the decline in the population of the endangered vaquita porpoise (Phocoena sinus). Manjarrez-Bringas et al.’s conclusions are incongruent with their own data, their logic is untenable, their analyses fail to consider current illegal fishing practices, and their recommendations are unjustified and misdirected. Vaquita face extinction because of bycatch, not because of the lack of river flow.

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