Diet diversity of jack and chub mackerels and ecosystem changes in the northern Humboldt Current system: A long-term study

Alegre, Ana; Bertrand, Arnaud; Espino, Marco; Espinoza, Pepe; Dioses, Teobaldo; Ñiquen, Miguel; Navarro, Iván; Simier, Monique; Ménard, Frédéric

doi:10.1016/j.pocean.2015.07.010

Cited by 20 publications

(15 citation statements)

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“…Here, we examine the trophic ecology of adult anchovies from northern Chile using stable isotope ratios of anchovies and their putative prey to estimate the relative role of phytoplankton and other prey, and to provide robust estimates of anchovy trophic position. Given the debate over the trophic ecology of anchovy, we compared their stable isotope values with that of juvenile jack mackerel, a known pelagic carnivore (Alegre et al, 2015; Orrego & Mendo, 2015).…”

Section: Introductionmentioning

confidence: 99%

Clarifying a trophic black box: stable isotope analysis reveals unexpected dietary variation in the Peruvian anchovy Engraulis ringens

Pizarro

Docmac

Harrod

2019

PeerJ

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Background Small fishes play fundamental roles in pelagic ecosystems, channelling energy and nutrients from primary producers to higher trophic levels. They support globally important fisheries in eastern boundary current ecosystems like the Humboldt Current System (HCS) of the SE Pacific (Chile and Peru), where fish catches are the highest in the world (per unit area). This production is associated with coastal upwelling where fisheries target small pelagic fishes including the Peruvian anchovy (Engraulis ringens). The elevated biomass attained by small pelagics is thought to reflect their low trophic position in short/simple food chains. Despite their global importance, large gaps exist in our understanding of the basic ecology of these resources. For instance, there is an ongoing debate regarding the relative importance of phytoplankton versus animal prey in anchovy diet, and ecosystem models typically assign them a trophic position (TP) of ∼2, assuming they largely consume phytoplankton. Recent work based on both relative energetic content and stable isotope analysis (SIA) suggests that this value is too low, with δ15N values indicating that anchovy TP is ca. 3.5 in the Peruvian HCS. Methods We characterised the trophic ecology of adult anchovies (n = 30), their putative prey and carnivorous jack mackerel (n = 20) captured from N Chile. SIA (δ13C and δ15N) was used to estimate the relative contribution of different putative prey resources. δ15N was used to estimate population level trophic position. Results Anchovies showed little variability in δ13C (−18.7 to −16.1‰) but varied greatly in δ15N (13.8 to 22.8‰)—individuals formed two groups with low or high δ15N values. When considered as a single group, mixing models indicated that anchovy diet was largely composed of zooplankton (median contribution: 95% credibility limits), with major contributions of crustacean larvae (0.61: 0.37–0.77) and anchovy (preflexion) larvae (0.15: 0.02–0.34), and the assimilation of phytoplankton was negligible (0.05: 0–0.22). The modal (95% credibility limits) estimate of TP for the pooled anchovy sample was 3.23 (2.93–3.58), overlapping with recent SIA-based estimates from Peru. When the two δ15N groups were analysed separately, our results indicate that the lower δ15N group largely assimilated materials from crustacean larvae (0.73: 0.42–0.88), with a TP of 2.91 (2.62–3.23). Mixing models suggested high δ15N anchovies were cannibalistic, consuming anchovy preflexion larvae (0.55: 0.11–0.74). A carnivorous trophic niche was supported by high TP (3.79: 3.48–4.16), mirroring that of carnivorous juvenile jack mackerel (Trachurus murphyi; 3.80: 3.51–4.14). Our results support recent conclusions regarding high TP values of anchovy from Peru and reveal new insights into their trophic behaviour. These results also highlight the existence of cryptic trophic complexity and ecosystem function in pelagic food webs, classically considered as simple.

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Section: Introductionmentioning

confidence: 99%

Clarifying a trophic black box: stable isotope analysis reveals unexpected dietary variation in the Peruvian anchovy Engraulis ringens

Pizarro

Docmac

Harrod

2019

PeerJ

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“…In contrast to jack mackerel, chub mackerel do not present a clear ontogenetic trend of consuming larger prey with increasing size; paradoxically, chub mackerel from all sizes foraged on small zooplankton (copepod) while small chub mackerel consume more fish than large chub mackerel (Alegre et al, 2015). Both jack mackerel and chub mackerel are considered opportunistic foragers, adapting their trophic behavior to prey accessibility (Alegre et al, 2015). Saury or needlefish (Scomberesox saurus scombroides) is a pelagic fish that was abundant off Peru during the 1970s, when sardine dominated the HCS, reaching an estimated biomass of 1 million tonnes in 1978 (Jordán et al, 1978).…”

Section: Jack Mackerel Chub Mackerel and Saurymentioning

confidence: 76%

“…It has a wide area of distribution, extending across the whole subtropical area of the South Pacific Ocean from South America to New Zealand (Gerlotto et al, 2012). The diet of jack mackerel varies with the fish size, the largest jack mackerel (>40 cm) feed on anchovy and other small pelagics, the mid-sized jack mackerels (between 20 and 40 cm) feed on zooplankton (mainly euphausiids), while the smallest feed on copepods (Alegre et al, 2015). Like sardine, jack mackerel distribution and abundance are associated with sub-surface oxygen concentrations over a wide variety of scales; they avoid areas where the oxygenated surface layer over a low oxygen water column is too thin (Bertrand et al, 2016).…”

Section: Jack Mackerel Chub Mackerel and Saurymentioning

confidence: 99%

“…The chub mackerel off Peru consumes more fish than jack mackerel, despite having a smaller maximum size (Alegre et al, 2015). In contrast to jack mackerel, chub mackerel do not present a clear ontogenetic trend of consuming larger prey with increasing size; paradoxically, chub mackerel from all sizes foraged on small zooplankton (copepod) while small chub mackerel consume more fish than large chub mackerel (Alegre et al, 2015). Both jack mackerel and chub mackerel are considered opportunistic foragers, adapting their trophic behavior to prey accessibility (Alegre et al, 2015).…”

Section: Jack Mackerel Chub Mackerel and Saurymentioning

confidence: 99%

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Fish debris in sediments from the last 25 kyr in the Humboldt Current reveal the role of productivity and oxygen on small pelagic fishes

Salvatteci

Gutiérrez

Field

et al. 2019

Progress in Oceanography

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Please note that this is an author-produced PDF of an article accepted for publication following peer review. The definitive publisher-authenticated version is available on the publisher Web site. in pelagic fish abundances have occurred in response to past large-scale climate changes than those observed in the instrumental period, which suggests that future climate change may result in substantial changes in ecosystem structure. Highlights ► Anchovy and other fishes fluctuated from multidecadal to millennial timescales. ► Productivity appears as the main factor controlling small pelagic fish abundance. ► Sub-surface oxygenation seems to play a role in a species-dependent way. ► The industrial fishery developed during a period of exceptional fish productivity.

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“…Off Peru, the chub mackerel is mainly associated with the water mass denominated Subtropical Surface Waters (SSW) (Sanchez et al 2000) usually forming large shoals especially beyond 160 nautical miles (Dioses 1995). This species is considered as an opportunistic omnivorous being the Peruvian anchovy, copepods and euphausiids their main prey (Alegre et al 2015). Because larger fishes, marine mammals and seabirds consume it, S. japonicus links lower trophic levels with top-predators, making this species play an important role in the NHCS trophic web.…”

Section: Introductionmentioning

confidence: 99%

High genetic connectivity and Population Expansion of Scomber japonicus in the Northern Humboldt Current System revealed by mitochondrial D-Loop region sequences

2017

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La caballa, Scomber japonicus soporta una pesquería importante en el Pacífico Sudeste, sin embargo, su genética de poblaciones se desconoce actualmente. En el presente estudio se examinó la estructura genética, el flujo génico y la demografía histórica de esta especie en la parte norte del Sistema de la Corriente de Humboldt. Las muestras fueron colectadas en los veranos del 2013 y 2014 en tres puntos de desembarco de pesca (Paita, Ventanilla e Ilo) cubriendo 12 grados de latitud frente a la costa peruana. Se secuenció un segmento de 532 pb de la región control mitocondrial en 72 individuos, el cual permitió detectar un total de 29 sitios polimórficos, 35 haplotipos, niveles moderados altos de diversidad haplotípica (0.793 – 0.969) y muy bajos niveles de diversidad nucleotídica (0.004 – 0.008). El análisis de flujo génico mostró altos niveles de conectividad entre las poblaciones en las áreas de muestreo. El análisis de varianza molecular (ФST = 0.00868, P = 0.1837), las comparaciones ФST a pares de poblaciones y las pruebas de diferenciación genética confirmaron la carencia de estructuración genética entre las tres localidades. Estos análisis sugieren que los sitios de muestreo analizados pueden ser considerados como un solo grupo genético. El comportamiento migratorio, el alto potencial de dispersión de los estadios tempranos de desarrollo y la ausencia de barreras oceanográficas pueden explicar su homogeneidad genética a lo largo del mar peruano. También se examinó la demografía histórica. Las pruebas de neutralidad, la distribución mismatch y el Bayesian Skyline Plot sugirieron un escenario de expansión poblacional que tuvo lugar durante el Pleistoceno Superior. Este estudio provee información nueva con respecto a la genética de poblaciones de la caballa en el Pacífico Sudeste.

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Diet diversity of jack and chub mackerels and ecosystem changes in the northern Humboldt Current system: A long-term study

Cited by 20 publications

References 46 publications

Clarifying a trophic black box: stable isotope analysis reveals unexpected dietary variation in the Peruvian anchovy Engraulis ringens

Clarifying a trophic black box: stable isotope analysis reveals unexpected dietary variation in the Peruvian anchovy Engraulis ringens

Fish debris in sediments from the last 25 kyr in the Humboldt Current reveal the role of productivity and oxygen on small pelagic fishes

High genetic connectivity and Population Expansion of Scomber japonicus in the Northern Humboldt Current System revealed by mitochondrial D-Loop region sequences

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