Investigating relationships between albacore tuna (Thunnus alalunga) CPUE and prey distribution in the Bay of Biscay
Introduction
Ecological systems exhibit heterogeneity over a broad range of scales, with marine organisms having an aggregated, patchy distribution on a wide variety of space and time scales from centimetres to thousands of kilometres (Wiebe, 1970, Steele, 1976, Haury et al., 1978, Mackas and Boyd, 1979, Mackas et al., 1985, Frontier, 1987, Russel et al., 1992, Davis et al., 1991, Bertrand et al., 2002b). Studying interactions between predator and prey implies choosing an appropriate space–time scale. This choice is difficult because populations and ecosystems cannot be described at a single scale (Levin, 1992). Processes at regional scales are more regular; its study being key to our understanding of trophic interactions among populations (Rose and Leggett, 1990). The relationships between tuna and their prey are generally studied at regional (1000s of km), meso (100s of km) and local (km) scales (Josse et al., 1998, Bertrand, 1999, Bertrand et al., 2002b, Goñi et al., 2009). The range of tuna distribution is known to be limited mainly due to hydrological conditions (Sharp, 1978, Sund et al., 1981, Brill, 1994, Bard, 2001, Bertrand et al., 2002a, Bertrand et al., 2002b); however, within areas of suitable abiotic conditions, tuna tend to be more abundant where prey are concentrated (Sund et al., 1981, Roger, 1994, Bertrand, 1999, Bertrand et al., 2002b).
Every summer, albacore tuna (Thunnus alalunga) perform seasonal feeding migrations into the Bay of Biscay. This area constitutes a hot spot for juvenile tuna in search of prey and sustains a traditional seasonal fishery, targeting albacore tuna from June to October. Catches occur off the shelf (but adjacent to the shelf break) from the Cantabric Coast (Fig. 1) up to 48°N (Santiago, 2004). So far, no effort has been put into producing combined studies of the spatial distribution of albacore tuna catches and their potential prey, predominantly small pelagic fish and euphausiids (Goñi, 2008).
Since 2003, annual acoustic surveys are undertaken, in autumn, in the Bay of Biscay (JUVENA Program, Boyra and Uriarte, 2006, Boyra et al., 2006). Although these surveys are executed to assess the abundance of juvenile anchovy and are under constraints imposed by management requirements, they partially overlap with the period and location of the albacore tuna baitboat and trolling fishing season in the Bay of Biscay. This makes JUVENA an important source of information, with acoustic data as a key tool, for the observation of the distribution and spatial–temporal structure of the pelagic community in the area.
The aim of this study was to examine how the spatial distribution and abundance of albacore tuna prey impact CPUE in the Bay of Biscay. Data come from the annual acoustic surveys (2003–2005) and CPUE logbook records from commercial fisheries. We used the description of interannual variation in the patterns of spatial distribution of small pelagic fish and euphausiids abundance as an indicator of food availability for albacore tuna. The relationships between presence and abundance of prey and albacore tuna were examined at both regional (study area) and local (44, 56 and 111 km) scales.
Section snippets
Albacore CPUE data
Daily catch rates of albacore tuna were obtained from the logbooks distributed in albacore tuna baitboat and trolling fisheries. The logbooks provided the following information on a daily basis: name of vessel, date and location (latitude and longitude) of the fishing set, number of specimens captured according to commercial category, type of bait used and sea surface temperature (SST).
Acoustic surveys
Information on tuna prey abundance and distribution were obtained from three acoustic surveys performed within
Spatial distribution of albacore tuna and prey
In 2003, most albacore tuna catches were located within the standard JUVENA area (Fig. 2), mainly over the Cap Ferret Canyon (Fig. 1) with occasional events occurring on the western part of the Cantabrian shelf break. Anchovies (mainly juvenile) were found distributed in monospecific schools along the shelf-break over the southern part of the Bay of Biscay, between 43°40′ and 44°50′N, and between 5° and 1°50′W (Fig. 2a). The amount of fluid-like plankton observed during this survey was very low
Discussion
In this study, we found that at an interannual scale more albacore tuna CPUE observations occurred inside the JUVENA area when prey were more abundant. However, negative correlations were obtained between albacore tuna CPUE outside the JUVENA area and the prey abundance inside the JUVENA area. These correlations were not significant but this may be because of the limited number of years considered in this study. Yet, due to the high r2 (always > 0.92, except in the case of fluid-like prey, Table 1
Acknowledgements
This work was supported by the JUVENA project funded by the Department of Agriculture and Fisheries of the Basque Government and the Ministry of Agriculture, Fishery and Food (MAPA), of the Spanish Government and a Grant to AL. (Technological Centre Foundation). We would like to thank all the skippers that kindly provided their logbooks and the crews of the commercial fishing vessels that took part in the JUVENA cruises. We are also grateful to the technical staff of AZTI (Carlota Perez, Iñaki
References (51)
Correction on school geometry and density: approach based on acoustic image simulation
Aquatic Living Resources
(2001)- et al.
Oceano-meteorological conditions in the SE Bay of Biscay for the period 2001–2005. A comparison with the last two decades
Journal of Marine Systems
(2008) - et al.
Trends and anomalies in sea surface temperature, observed over the last 60 years, within the southeastern Bay of Biscay
Continental Shelf Research
(2009) - et al.
Could Biscay Bay Anchovy recruit through a “Bakunian” loophole?
Progress in Oceanography
(2007) Behavioral and physiological properties of tunas and their effects on vulnerability to fishing gear
- et al.
Relationships between frontal structures and zooplankton communities along a cross shelf transect in the Bay of Biscay (1995 to 2003)
Marine Ecology Progress Series
(2004) - et al.
Fine scale zooplankton distribution in the Bay of Biscay in spring 2004
Journal of Plankton Research
(2007) Extension of the geographical and vertical habitat of albacore (T. Alalunga) in the North Atlantic. Possible consequences on true rate of exploitation of this stock
ICCAT Collective Volume of Scientific Papers
(2001)- et al.
Ocean climate and prey availability affect the trophic level and reproductive success of the marbled murrelet, an endangered seabird
Marine Ecology Progress Series
(2007) - Bertrand, A., 1999. Le système thon-environnement en Polynése Française: caractérisation de l’habitat pélagique, étude...
Tuna food habits related to the micronekton distribution in French Polynesia
Marine Biology
Hydrological and trophic characteristics of tuna habitat: consequences on tuna distribution and longline catchability
Canadian Journal of Fisheries and Aquatic Sciences
A review of temperature and oxygen tolerance studies of tunas pertinent to fisheries oceanography, movement models and stocks assessments
Fisheries Oceanography
Micropatchiness, turbulence and recruitment in plankton
Journal of Marine Research
Applications of fractal theory to ecology
Small scale vertical behaviour of juvenile albacore in relation to their biotic environment in the Bay of Biscay
Metabolic Rate of the albacore tuna Thunnus alalunga
Marine Biology
Patterns and processes in the time-space scales of plankton distributions
From egg to juvenile in the Bay of Biscay: spatial patterns of anchoy (Engraulis encrasicolus) recruitment in a non-upwelling region
Fisheries Oceanography
Simultaneous observations of tuna movements and their prey by sonic tracking and acoustic surveys
Hydrobiologia
Cited by (20)
Global habitat preferences of commercially valuable tuna
2015, Deep-Sea Research Part II: Topical Studies in OceanographyCitation Excerpt :Maury et al. (2001) suggested that low salinities could indicate favourable trophic areas induced by fluvial water supplies. In fact, trophic resources must play a major role in the spatial distribution of tunas, as suggested by several relatively small scale studies (Bestley et al., 2009; Lezama-Ochoa et al., 2010; Schick and Lutcavage, 2009) and the fact that tunas conduct, as part of their life cycles, extensive trophic migrations to exploit seasonally productive areas (e.g. Dufour et al. 2010, Fonteneau et al., 2008). In this study, we have used DCHL and ZOO as simple proxies for prey concentration, but trophodynamics of tunas are complex and dynamic (Young et al., 2015).
Comparative ecology of widely distributed pelagic fish species in the North Atlantic: Implications for modelling climate and fisheries impacts
2014, Progress in OceanographyCitation Excerpt :Further, since the feeding habitat is defined based on accessibility to diverse prey functional groups (Lehodey et al., 2010a), the model predicts also the diet by age and its spatio-temporal variability. These predictions will be compared to the information collected at sea (e.g., Lezama-Ochoa et al., 2010). Finally, climate change impacts on albacore population will be explored using environmental forcing produced by IPCC climate models (Lehodey et al., 2010b).
Relationship of Northeast Atlantic albacore juveniles with surface thermal and chlorophyll-a fronts
2014, Deep-Sea Research Part II: Topical Studies in OceanographyCitation Excerpt :Obviously, albacore do not eat Chl-a but prey that might be linked to those fronts. As a matter of fact, Lezama-Ochoa et al. (2010) suggested that the distribution of albacore might be linked to that of anchovy, one of the main preys of albacore (Goñi et al., 2011). This indirect link to Chl-a fronts might partly explain the lack of association to Chl-a fronts as analysed in this study.
New insights to behaviour of North Atlantic albacore tuna (Thunnus alalunga) observed with pop-up satellite archival tags
2014, Fisheries ResearchCitation Excerpt :In terms of our knowledge of factors affecting NA albacore depth preferences, temporal (diel, seasonal and inter-annual), spatial and albacore size related variability in prey composition has been demonstrated with deep foraging thought to occur in offshore locations (Goñi et al., 2011; Hassani et al., 1997; Pusineri et al., 2005; Lezama et al., 2010). A number of studies have revealed significant effects of climatic and environmental variables on NA albacore by correlating catch data with oceanographic conditions averaged over time and space (Dufour et al., 2010; Goñi and Arrizabalaga, 2005; Lezama et al., 2010; Sagarminaga and Arrizabalaga, 2010) but direct observations, particularly in relation to vertical distribution, using either acoustic telemetry or archival tags are required to produce data suitable for input to habitat based models (Brill et al., 2005). Direct observations of NA albacore are limited to one short term ultrasonic tracking study carried out in a localised area in the south east corner of the Bay of Biscay (Goñi et al., 2009).
Environmental DNA in the Kuroshio reveals environment-dependent distribution of economically important small pelagic fish
2023, Frontiers in Marine Science