The box-balance model: a new tool to assess fish larval survival, applied to field data on two small pelagic fish

2020 ◽  
Vol 650 ◽  
pp. 289-308 ◽  
Author(s):  
V Raya ◽  
J Salat ◽  
A Sabatés

This work develops a new method, the box-balance model (BBM), to assess the role of hydrodynamic structures in the survival of fish larvae. The BBM was applied in the northwest Mediterranean to field data, on 2 small pelagic fish species whose larvae coexist in summer: Engraulis encrasicolus, a dominant species, and Sardinella aurita, which is expanding northwards in relation to sea warming. The BBM allows one to quantify the contribution of circulation, with significant mesoscale activity, to the survival of fish larvae, clearly separating the effect of transport from biological factors. It is based on comparing the larval abundances at age found in local target areas, associated with the mesoscale structures (boxes), to those predicted by the overall mortality rate of the population in the region. The application of the BBM reveals that dispersion/retention by hydrodynamic structures favours the survival of E. encrasicolus larvae. In addition, since larval growth and mortality rates of the species are required parameters for application of the BBM, we present their estimates for S. aurita in the region for the first time. Although growth and mortality rates found for S. aurita are both higher than for E. encrasicolus, their combined effect confers a lower survival to S. aurita larvae. Thus, although the warming trend in the region would contribute to the expansion of the fast-growing species S. aurita, we can confirm that E. encrasicolus is well established, with a better adapted survival strategy.

2009 ◽  
Vol 24 (2) ◽  
pp. 153
Author(s):  
G. Aceves-Medina ◽  
C. J. Robinson ◽  
R. Palomares-García ◽  
J. Gómez-Gutierrez

Análisis de la distribucion vertical de la abundancia de larvas de peces pelágicos menores en el Golfo de California mediante videocámaras submarinas Se utilizaron dos tipos de videocámaras submarinas para estudiar la distribución y abundancia vertical de larvas de los peces pelágicos menores Engraulis mordax, Etrumeus teres y Sardinops sagax a 1 m de resolución, en una localidad en el norte del Golfo de California con condiciones de calma y alta densidad de sardinas adultas. La mayor abundancia promedio (900 larvas m -1 min -1 ) se encontró inmediatamente arriba de la termoclina (33 m) y la picnoclina (36 m), aparentemente no asociada al máximo de clorofila detectado en superficie, ni a la mayor densidad de peces adultos (10 -20 m). Las observaciones con video permitieron determinar la distribución vertical a una resolución imposible de obtener mediante muestreos con redes; sin embargo, esta es una técnica poco útil en zonas con elevada velocidad de las corrientes.


2019 ◽  
Vol 617-618 ◽  
pp. 113-136 ◽  
Author(s):  
S Somarakis ◽  
S Tsoukali ◽  
M Giannoulaki ◽  
E Schismenou ◽  
N Nikolioudakis

Author(s):  
Amelian Dinisia ◽  
Enan M. Adiwilaga ◽  
. Yonvitner

ABSTRACT<br /><br />Millions of organisms can be found in the Cenderawasih Gulf National Park area, especially in the waters of the Kwatisore Bay, Nabire and has been well-known to almost all over the world. Large zooplankton is an important food for migrated fish larvae and all kinds of fish including anchovies. Anchovy is the food of large and small pelagic fish groups. Groups of fish that use plankton as food were included anchovy. The main catch product of lift net at the Kwatisore bay is anchovy (Stolephorus spp.). This study aims to assess the level of availability of anchovy in relation to the abundance of zooplankton as food and to analyze the influence of anchovy fishing activities with lift net fishing gear. The results were obtained 51 species of zooplankton, which consists of 44 types holoplankton and 7 types of meroplankton. There were 17 species of zooplankton were found in the stomach of anchovy with the subgroup dominated by copepods (73.51 %). Among 17 species of zooplankton there 2 types that were found in all four sampling periods, namely Calanus sp. 2 and Euterpina acutifrons. There is a relationship between the abundance of individual zooplankton in the waters of the anchovy biomass and also between the abundance of zooplankton and biomass of anchovy.<br /><br />Keywords: abundance of zooplankton, biomass of anchovy, lift net at Kwatisore<br />-------<br /><br />ABSTRAK<br /><br />Jutaan organisme dapat ditemukan dalam kawasan Taman Nasional Teluk Cenderawasih khususnya di perairan Kwatisore, Nabire dan telah terkenal sampai hampir ke seluruh dunia. Zooplankton berukuran besar merupakan makanan penting bagi ikan-ikan yang bermigrasi dan larva semua jenis ikan termasuk didalamnya ikan teri. Ikan teri merupakan makanan dari kelompok ikan pelagis besar dan kecil. Kelompok ikan-ikan yang banyak memanfaatkan plankton dari kelompok ikan pelagis kecil diantaranya ikan teri. Hasil tangkapan utama bagan penangkap ikan pelagis kecil di perairan Kwatisore ialah jenis teri (Stolephorus sp.). Tujuan penelitian ini adalah untuk mengkaji tingkat ketersediaan ikan teri dalam kaitannya dengan kelimpahan zooplankton sebagai makanannya serta menganalisis pengaruh dari aktivitas penangkapan ikan teri dengan alat tangkap bagan. Secara keseluruhan dari seluruh stasiun dalam setiap periode sampling, diperoleh 51 jenis zooplankton yang terdiri atas 44 jenis holoplankton dan 7 jenis meroplankton. Terdapat 17 jenis zooplankton yang ditemukan dalam lambung ikan teri dengan didominasi oleh Sub-grup Copepoda (73,51%). Diantara ke-17 jenis zooplankton tersebut terdapat 2 jenis yang ditemukan pada keempat periode sampling yaitu Calanus Sp.2 dan Euterpina acutifrons. Hasil analisis regresi linier antara biomassa ikan teri hasil tangkapan bagan dan kelimpahan maupun antara biomassa ikan teri hasil tangkapan bagan dan jumlah jenis zooplankton menunjukkan adanya korelasi positif.<br /><br />Kata kunci: kelimpahan zooplankton, biomassa ikan teri, bagan di Kwatisore


Animals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 505
Author(s):  
Luz Hurtado ◽  
Claudio D. Miranda ◽  
Rodrigo Rojas ◽  
Félix A. Godoy ◽  
Mark A. Añazco ◽  
...  

The culture of red cusk eel Genypterus chilensis is currently considered a priority for Chilean aquaculture but low larval survival rates have prompted the need for the continuous use of antibacterials. The main aim of this study was to evaluate the role of live feed as a source of antibacterial-resistant bacteria in a commercial culture of G. chilensis. Samples of rotifer and Artemia cultures used as live feed were collected during the larval growth period and culturable bacterial counts were performed using a spread plate method. Rotifer and Artemia cultures exhibited high levels of resistant bacteria (8.03 × 104 to 1.79 × 107 CFU/g and 1.47 × 106 to 3.50 × 108 CFU/g, respectively). Sixty-five florfenicol-resistant isolates were identified as Vibrio (81.5%) and Pseudoalteromonas (15.4%) using 16S rRNA gene sequence analysis. A high incidence of resistance to streptomycin (93.8%), oxytetracycline (89.2%), co-trimoxazole (84.6%), and kanamycin (73.8%) was exhibited by resistant isolates. A high proportion of isolates (76.9%) carried the florfenicol-resistance encoding genes floR and fexA, as well as plasmid DNA (75.0%). The high prevalence of multiresistant bacteria in live feed increases the incidence of the resistant microbiota in reared fish larvae, thus proper monitoring and management strategies for live feed cultures appear to be a priority for preventing future therapy failures in fish larval cultures.


2020 ◽  
Vol 153 ◽  
pp. 01005
Author(s):  
Umi Chodrijah ◽  
Ria Faizah ◽  
Tirtadanu

Big eye scad (Selar crumenophthalmus) is one of important small pelagic fish which is exploited in Kwandang waters-Sulawesi Sea. The exploitation of this species has been increasing every year. This research was carried out to study the growth, mortality and exploitation of bigeye scad in the Kwandang waters during January-November 2016. The von Bertalanffy growth equation was derived as Lt = 25.95(1 - e 1,01(t+-0.16374)) with length between 14.9 -26.4 cm FL (average length 18,64 cm). The size at first capture (Lc) was estimated as 18.69 cm. The total, natural and fishing mortality rates were assessed as 4.28, 1.90 and 2.38 year−1, respectively. The exploitation rate (E) of 0.56 per year indicates that the degree of harvesting leads to a more capture condition.. The management that must be applied is to reduce fishing efforts to 12% of the current situation and to consider temporarily closing fishing activities (closing season).


2017 ◽  
Vol 569 ◽  
pp. 187-203 ◽  
Author(s):  
AM McInnes ◽  
PG Ryan ◽  
M Lacerda ◽  
J Deshayes ◽  
WS Goschen ◽  
...  

Author(s):  
Yolanda MTN Apituley ◽  
Dionisius Bawole ◽  
Imelda KE Savitri ◽  
Friesland Tuapettel

This research was taken in Ambon (Latuhalat and Laha) and in Central Maluku Regency (Waai) in May – July 2018. It was aimed at mapping the value chain of small pelagic fish in Ambon through: 1) mapping of product, financial and information flows and 2). analysis of percentage distribution of small pelagic fish caught. The data used in this study was primary and secondary data, and analyzed by using value chain analysis. The results show that small pelagic fish marketing chain in Ambon consisted of six models with five actors. Each chain is formed due to the conditions and situation of market, resulted by the influencing of catches of fishermen and traders' capital. The broker plays an important role in marketing small pelagic fish in the market and obtaining 10% of the fishermen's catch that can be distributed, both to retailers and cold storage. Fish caught by the fishermen is still fresh in general when arrives in the consumers, because the fishing area is not too far, the market distance with the production centers is also quite close and in general fishermen and traders have understood the importance of maintaining product quality. Even so, the role of the Government in providing marketing facilities and infrastructure is needed so that modern market conditions can be applied in marketing fresh fish in Ambon.


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