Large Squid Research Articles

Bathyal feasting: post-spawning squid as a source of carbon for deep-sea benthic communities.

In many oceanic carbon budgets there is a discrepancy between the energetic requirements of deep-sea benthic communities and the supply of organic matter. This suggests that there are unidentified and unmeasured food sources reaching the seafloor. During 11 deep-sea remotely operated vehicle (ROV) surveys in the Gulf of California, the remains (squid carcasses and hatched-out egg sheets) of 64 post-brooding squid were encountered. As many as 36 remains were encountered during a single dive. To our knowledge this is one of the largest numbers of natural food falls of medium-size deep-sea nekton described to date. Various deep-sea scavengers (Ophiuroidea, Holothuroidea, Decapoda, Asteroidea, Enteropneusta) were associated with the remains. Although many of the 80 examined ROV dives did not encounter dead squids or egg sheets (n = 69), and the phenomenon may be geographically and temporally restricted, our results show that dead, sinking squid transport carbon from the water column to the seafloor in the Gulf of California. Based on food fall observations from individual dives, we estimate that annual squid carcass depositions may regionally contribute from 0.05 to 12.07 mg C m-2 d-1 to the seafloor in the areas where we observed the remains. The sinking of squid carcasses may constitute a significant but underestimated carbon vector between the water column and the seafloor worldwide, because squid populations are enormous and are regionally expanding as a result of climate change and pressure on fish stocks. In the future, standardized methods and surveys in geographical regions that have large squid populations will be important for investigating the overall contribution of squid falls to regional carbon budgets.

Deep pelagic food web structure as revealed by in situ feeding observations.

Food web linkages, or the feeding relationships between species inhabiting a shared ecosystem, are an ecological lens through which ecosystem structure and function can be assessed, and thus are fundamental to informing sustainable resource management. Empirical feeding datasets have traditionally been painstakingly generated from stomach content analysis, direct observations and from biochemical trophic markers (stable isotopes, fatty acids, molecular tools). Each approach carries inherent biases and limitations, as well as advantages. Here, using 27 years (1991–2016) of in situ feeding observations collected by remotely operated vehicles (ROVs), we quantitatively characterize the deep pelagic food web of central California within the California Current, complementing existing studies of diet and trophic interactions with a unique perspective. Seven hundred and forty-three independent feeding events were observed with ROVs from near-surface waters down to depths approaching 4000 m, involving an assemblage of 84 different predators and 82 different prey types, for a total of 242 unique feeding relationships. The greatest diversity of prey was consumed by narcomedusae, followed by physonect siphonophores, ctenophores and cephalopods. We highlight key interactions within the poorly understood ‘jelly web’, showing the importance of medusae, ctenophores and siphonophores as key predators, whose ecological significance is comparable to large fish and squid species within the central California deep pelagic food web. Gelatinous predators are often thought to comprise relatively inefficient trophic pathways within marine communities, but we build upon previous findings to document their substantial and integral roles in deep pelagic food webs.

Isotopic niche width differentiation between common bottlenose dolphin ecotypes and sperm whales in the Gulf of California

AbstractWorld populations or stock distinction of Tursiops truncatus has been difficult to assess, because of large variations in morphology, habitat, feeding habits, and social structure among areas, which may reflect phylogenetic segregation or ecological plasticity. In the Gulf of California, Mexico, two common bottlenose dolphin ecotypes (inshore and offshore) have been reported. The offshore ecotype is frequently observed in association with sperm whales (Physeter macrocephalus) but the reason for this is still unknown. To explore the degree of resource partitioning/overlap between these species and stocks, we used skin stable isotope values (δ13C, δ15N) to estimate quantitative metrics of isotopic niche width (Bayesian standard ellipse areas, SEAB) and estimated their diet composition using Bayesian isotopic mixing models. The inshore ecotype in different regions (north, central, and south) of the Gulf of California exhibited distinct δ15N values and SEAB, suggesting a latitudinal gradient in nitrogen sources of coastal localities. The SEAB of inshore and offshore bottlenose dolphin ecotypes was completely distinct, indicating resource partitioning. Associated offshore ecotype and sperm whales had overlapping SEAB. The isotopic mixing model indicates that a considerable proportion of both species’ diet is large Humbolt squid. Our results suggest that resource partitioning and species association are two strategies that bottlenose dolphin ecotypes use in this zone.

Large voltage modulation in superconducting quantum interference devices with submicron-scale step-edge junctions

A promising direction to improve the sensitivity of a SQUID is to increase its junction's normal resistance value, Rn, as the SQUID modulation voltage scales linearly with Rn. As a first step to develop highly sensitive single layer SQUID, submicron scale YBCO grain boundary step edge junctions and SQUIDs with large Rn were fabricated and studied. The step-edge junctions were reduced to submicron scale to increase their Rn values using focus ion beam, FIB and the measurement of transport properties were performed from 4.3 to 77 K. The FIB induced deposition layer proves to be effective to minimize the Ga ion contamination during the FIB milling process. The critical current–normal resistance value of submicron junction at 4.3 K was found to be 1–3 mV, comparable to the value of the same type of junction in micron scale. The submicron junction Rn value is in the range of 35–100 Ω, resulting a large SQUID modulation voltage in a wide temperature range. This performance promotes further investigation of cryogen-free, high field sensitivity SQUID applications at medium low temperature, e.g. at 40–60 K.

Diet Composition and Trophic Ecology of Northeast Pacific Ocean Sharks.

Although there is a general perception of sharks as large pelagic, apex predators, most sharks are smaller, meso- and upper-trophic level predators that are associated with the seafloor. Among 73 shark species documented in the eastern North Pacific (ENP), less than half reach maximum lengths >200cm, and 78% occur in demersal or benthic regions of the continental shelf or slope. Most small (≤200cm) species (e.g., houndsharks) and demersal, nearshore juveniles of larger species (e.g., requiem sharks) consume small teleosts and decapod crustaceans, whereas large species in pelagic coastal and oceanic environments feed on large teleosts and squids. Several large, pelagic apex predator species occur in the ENP, but the largest species (i.e., Basking Shark, Whale Shark) consume zooplankton or small nekton. Size-based dietary variability is substantial for many species, and segregation of juvenile and adult foraging habitats also is common (e.g., Horn Shark, Shortfin Mako). Temporal dietary differences are most pronounced for temperate, nearshore species with wide size ranges, and least pronounced for smaller species in extreme latitudes and deep-water regions. Sympatric sharks often occupy various trophic positions, with resource overlap differing by space and time and some sharks serving as prey to other species. Most coastal species remain in the same general region over time and feed opportunistically on variable prey inputs (e.g., season migrations, spawning, or recruitment events), whereas pelagic, oceanic species actively seek hot spots of prey abundance that are spatiotemporally variable. The influence of sharks on ecosystem structure and regulation has been downplayed compared to that of large teleosts species with higher per capita consumption rates (e.g., tunas, billfishes). However, sharks also exert indirect influences on prey populations by causing behavioural changes that may result in restricted ranges and reduced fitness. Except for food web modelling efforts in Alaskan waters, the trophic impacts of sharks are poorly incorporated into current ecosystem approaches to fisheries management in the NEP.

Characterization of large two-dimensional YBa2Cu3O7–δSQUID arrays

Large two-dimensional SQUID arrays were made using the step-edge Josephson junction process. The performance of the arrays is analyzed with respect to determining the conditions under which the optimal performance is achieved. We find that optimization of the field-voltage transfer function VB is reached at a specific temperature and device current bias point, and arrive at an empirical expression describing the dependence of VB on the critical current and dynamic resistance of the SQUID array and as a function of temperature. The empirical expression for VB of the SQUID arrays is similar to that given by well known theoretical models for a single SQUID.

Ensemble squid habitat model using three-dimensional ocean data

Abstract Neon flying squid (Ommastrephes bartramii) is a large pelagic squid internationally harvested in the North Pacific. Here, we examined its potential habitat in the central North Pacific using an ensemble modelling approach. Initially, ten statistical models were constructed by combining the squid fishing points, selected vertical layers of the sea temperature and salinity, sea surface height (SSH), and SSH gradient from the multi-variate ocean variational estimation system for the western North Pacific from June to July 1999–2011. The variable selection analyses have captured the importance of vertical temperature and salinity layers at the upper 300 and 440 m, respectively, coinciding with the reported vertical ranges of diel migration for the squid's primary prey species in the North Pacific. The evaluation of the habitat predictions using the independent sets of the presence data from 2012 to 2014 showed significant variability in the predictive accuracy, which is likely reflective of the interannual differences in environmental conditions across the validation periods. Our findings from ensemble habitat model approach using three-dimensional oceanographic data were able to characterize the near- and subsurface habitats of the neon flying squid. Moreover, our results underpinned the possible link between interannual environmental variability and spatio-temporal patterns of potential squid habitats. As such, these further suggest that an ensemble model approach could present a promising tool for operational fishery application and squid resource management.

Assessing the structure and temporal dynamics of seabird communities: the challenge of capturing marine ecosystem complexity.

Summary Understanding interspecific interactions, and the influences of anthropogenic disturbance and environmental change on communities, are key challenges in ecology. Despite the pressing need to understand these fundamental drivers of community structure and dynamics, only 17% of ecological studies conducted over the past three decades have been at the community level.Here, we assess the trophic structure of the procellariiform community breeding at South Georgia, to identify the factors that determine foraging niches and possible temporal changes. We collected conventional diet data from 13 sympatric species between 1974 and 2002, and quantified intra‐ and inter‐guild, and annual variation in diet between and within foraging habits. In addition, we tested the reliability of stable isotope analysis (SIA) of seabird feathers collected over a 13‐year period, in relation to those of their potential prey, as a tool to assess community structure when diets are diverse and there is high spatial heterogeneity in environmental baselines.Our results using conventional diet data identified a four‐guild community structure, distinguishing species that mainly feed on crustaceans; large fish and squid; a mixture of crustaceans, small fish and squid; or carrion. In total, Antarctic krill Euphausia superba represented 32%, and 14 other species a further 46% of the combined diet of all 13 predators, underlining the reliance of this community on relatively few types of prey. Annual variation in trophic segregation depended on relative prey availability; however, our data did not provide evidence of changes in guild structure associated with a suggested decline in Antarctic krill abundance over the past 40 years.Reflecting the differences in δ15 N of potential prey (crustaceans vs. squid vs. fish and carrion), analysis of δ15 N in chick feathers identified a three‐guild community structure that was constant over a 13‐year period, but lacked the trophic cluster representing giant petrels which was identified using conventional diet data.Our study is the first in recent decades to examine dietary changes in seabird communities over time. Conventional dietary analysis provided better resolution of community structure than SIA. However, δ15 N in chick feathers, which reflected trophic (level) specialization, was nevertheless an effective and less time‐consuming means of monitoring temporal changes.

Seabirds and climate: knowledge, pitfalls, and opportunities

As a physical driver of ecosystem functioning, it is not surprising that climate influences seabird demography and population dynamics, generally by affecting food availability. However, if we zoom in ecologically, seabirds are in fact very heterogeneous, ranging in size from very small to very large species (with a difference of more than two orders of magnitude in body weight), from planktivorous forms to predators of large fish and squid, from benthic to pelagic, from species with small foraging ranges to species feeding throughout the whole circumpolar region, and from resident species (at a spatial mesoscale) to trans-equatorial migrating seabirds that travel large distances across several oceanographic systems. Due to this high variability and the difficulty in obtaining direct reliable estimates of long-term food availability, global climatic indices have been extensively used in studying seabird demography and population dynamics. However, the use made by researchers of these indices has certain conceptual and methodological pitfalls, which I shall address in this review. Other factors, such as anthropogenic impacts (including oil-spills and interaction with fisheries), may further alter or confound the association between climate and seabird demography. These pitfalls and environmental noise, together with the inability to incorporate resilience, may bias our predictions regarding the future impact of global warming on seabirds, many of which have vulnerable populations.

Largest squid have lowest anaerobic metabolic capacities

![][1] Hunting beneath the waves comes with its own unique set of challenges. As swimming predators grow, the drag holding them back increases when they speed up, and the chances of being detected by their victim also increase, so stalkers have to mount an even greater burst of speed

HTS ion damage Josephson junction technology for SQUID arrays

The high temperature superconducting (HTS) Josephson Junction (JJ) ion damage technology we are developing is well suited for making large SQUID arrays. We have studied arrays of similar SQUIDs together with large SQIFs (Superconducting Quantum Interference Filter) with 2000 SQUIDs of different loop areas. Magnetic field sensitivity has been measured in both types of devices as a function of bias current and temperature. The effects of the barrier thickness (from 20 to 80 nm) and JJ length (2 or 5 μm) on characteristics have been investigated.

Ecosystem functioning in the Mozambique Channel: Synthesis and future research

The MESOBIO programme investigated mesoscale dynamics using an integrated ecosystem approach, linking physical and biogeochemical processes with different trophic levels. Observation and modeling were used in combination to explain the main processes occurring in the mesoscale eddy field. The particular shape of the Mozambique Channel, composed of two basins interconnected through a narrow zone, favours the generation of mesoscale eddies and increases the opportunity for eddy-shelf interactions. Phytoplankton abundance peaked in areas of nutrient enrichment that are often found in the core of cyclonic eddies, as well as on the continental shelf. Grazers in zooplankton communities exhibited high biovolume in cyclonic eddies, but their abundance was lower in fronts and divergence zones, with lowest biovolume in anticyclones. Biovolume was highest at shelf stations, but very variable and similar to phytoplankton. Age of eddies, their subsequent maturation stage and the dynamics of the eddy field played a major role effecting zooplankton abundance. Micronekton presented abundance patterns coherent with zooplankton distribution, however this was only demonstrated by acoustic methods, whereas mid-water trawl collection and predators stomach contents (predators being used as biological samplers) did not reveal significant relationships with mesoscale features. For upper trophic levels, the average density of foraging seabirds was lowest in anticyclones, highest in cyclones and at intermediate levels in divergence, shelf and frontal zones. However, multifaceted behavioral responses were observed in such a highly variable environment. Swordfish was clearly associated with divergence zones, and to a lesser extent with fronts, suggesting that the higher density in divergences was related to the presence of its main prey, essentially large squids. Although tunas tended to be more abundant in areas with weak geostrophic currents, their relationship to mesoscale features was not straightforward as adult tunas caught by longline have the ability to explore different foraging habitats over a broad range of depths. Several suggestions for advancing eddy-related research from the current state of knowledge are proposed in the second part of the paper.

VMS-based fishing effort and population demographics for the European squid (Loligo vulgaris) off the Portuguese coast

This study presents a 1-year synopsis of the trawl fishery for the European squid Loligo vulgaris in Portuguese waters, integrating length-structured landings with corresponding geo-referenced fishing activities. From vessel monitoring system (VMS) data, landings and biological sampling, a “status-report” was obtained for 2003. Fishing pressure was found to be most intense in inshore areas of the northwest and the south coasts. Population size structure, classified into three categories, was not uniform throughout the fishing areas. Larger squid are found offshore in the northwest (International Council for the Exploration of the Sea—ICES rectangle 10E0) and in the south (rectangles 2E1 and 3E1), whereas all inshore western coast rectangles showed larger proportions of small squid relative to the southern rectangles. The analysis carried out in this study provides an insight into the possible impact of the fishing intensity pattern on the population structure in various zones. The results demonstrate the benefits of combining geo-referenced fisheries information with landings and size data, to produce explicit spatio-temporal information that can contribute to integrated planning and management for the sustainable exploitation of this resource.

Extreme plasticity in life‐history strategy allows a migratory predator (jumbo squid) to cope with a changing climate

Dosidicus gigas (jumbo or Humboldt squid) is a semelparous, major predator of the eastern Pacific that is ecologically and commercially important. In the Gulf of California, these animals mature at large size (>55cm mantle length) in 1-1.5years and have supported a major commercial fishery in the Guaymas Basin during the last 20years. An El Niño event in 2009-2010, was accompanied by a collapse of this fishery, and squid in the region showed major changes in the distribution and life-history strategy. Large squid abandoned seasonal coastal-shelf habitats in 2010 and instead were found in the Salsipuedes Basin to the north, an area buffered from the effects of El Niño by tidal upwelling and a well-mixed water column. The commercial fishery also relocated to this region. Although large squid were not found in the Guaymas Basin from 2010 to 2012, small squid were abundant and matured at an unusually small mantle-length (<30cm) and young age (approximately 6months). Juvenile squid thus appeared to respond to El Niño with an alternative life-history trajectory in which gigantism and high fecundity in normally productive coastal-shelf habitats were traded for accelerated reproduction at small size in an offshore environment. Both small and large mature squid, were present in the Salsipuedes Basin during 2011, indicating that both life- history strategies can coexist. Hydro-acoustic data, reveal that squid biomass in this study area nearly doubled between 2010 and 2011, primarily due to a large increase in small squid that were not susceptible to the fishery. Such a climate-driven switch in size-at-maturity may allow D. gigas to rapidly adapt to and cope with El Niño. This ability is likely to be an important factor in conjunction with longerterm climate-change and the potential ecological impacts of this invasive predator on marine ecosystems.

Range Expansion of the Jumbo Squid in the NE Pacific: δ15N Decrypts Multiple Origins, Migration and Habitat Use

Coincident with climate shifts and anthropogenic perturbations, the highly voracious jumbo squid Dosidicus gigas reached unprecedented northern latitudes along the NE Pacific margin post 1997–98. The physical or biological drivers of this expansion, as well as its ecological consequences remain unknown. Here, novel analysis from both bulk tissues and individual amino acids (Phenylalanine; Phe and Glutamic acid; Glu) in both gladii and muscle of D. gigas captured in the Northern California Current System (NCCS) documents for the first time multiple geographic origins and migration. Phe δ15N values, a proxy for habitat baseline δ15N values, confirm at least three different geographic origins that were initially detected by highly variable bulk δ15N values in gladii for squid at small sizes (<30 cm gladii length). In contrast, bulk δ15N values from gladii of large squid (>60 cm) converged, indicating feeding in a common ecosystem. The strong latitudinal gradient in Phe δ15N values from composite muscle samples further confirmed residency at a point in time for large squid in the NCCS. These results contrast with previous ideas, and indicate that small squid are highly migratory, move into the NCCS from two or more distinct geographic origins, and use this ecosystem mainly for feeding. These results represent the first direct information on the origins, immigration and habitat use of this key “invasive” predator in the NCCS, with wide implications for understanding both the mechanisms of periodic D. gigas population range expansions, and effects on ecosystem trophic structure.

Amplifier development for multiplexed cryogenic detectors

We make some considerations on the question of driving the cable from the cryogenic stage of refrigerators to the room temperature, in the case of multiplexed detector array systems where a high total Shannon information capacity is required. We have constructed large SQUID arrays for the purpose, some of which exhibit lower than 5 × 10−8 Φ0 Hz−1/2 flux noise at 4.2 K and do not require magnetic shielding in a typical laboratory environment. The option of using class-D amplifiers to reduce the cryogenic heat load is briefly reviewed.

Hypoxia tolerance and antioxidant defense system of juvenile jumbo squids in oxygen minimum zones

Jumbo squid (Dosidicus gigas) is a large oceanic squid endemic off the Eastern Tropical Pacific that undertakes diel vertical migrations into mesopelagic oxygen minimum zones. One of the expected physiological effects of such migration is the generation of reactive oxygen species (ROS) at the surface, promoted by the transition between hypoxia and reoxygenation states. The aim of this study was to investigate the energy expenditure rates and the antioxidant stress strategies of juvenile D. gigas under normoxia and hypoxia, namely by quantifying oxygen consumption rates, antioxidant enzyme activities [including superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST)], heat shock protein expression (Hsp70/Hsc70), and lipid peroxidation [malondialdehyde (MDA) levels]. A high significant decrease (68%) in squid’s metabolic rates was observed during hypoxia (p<0.05). This process of metabolic suppression was followed by a significant increase in Hsp70/Hsc70 expression (p<0.05), which may be interpreted as a strategy to prevent post-hypoxic oxidative damage during the squid’s night upwards migration to the surface ocean. On the other hand, in normoxia, the higher SOD and CAT activities seemed to be a strategy to cope with the reoxygenation process, and may constitute an integrated stress response at shallower depths. GST activity and MDA concentrations did not change significantly from normoxia to hypoxia (p>0.05), with the latter indicating no enhancement of lipid peroxidation (i.e. cellular damage) at the warmer and normoxic surface waters. The understanding of such physiological strategies that are linked to oxygen deprivation and reoxygenation phases may provide valuable information about how this species is quickly responding to the impacts of environmental stressors coupled with global climate change.

Optimization of battery strengths in the Hodgkin-Huxley model

Simulations show that neurons are capable of operating over a much broader range of values of ionic reversal potentials than what is actually observed. Since the reversal potentials, which depend on the ionic concentration gradients across the membrane, have strong effects on the signaling properties and metabolic energy consumption rates of neurons, it is natural to hypothesize that the actual values are optimal for some functional property of the neuron involving energy and information, much as the ion channel densities and leak conductance appear to be [1,2]. Here we consider the Hodgkin-Huxley model of the squid giant axon and systematically investigate whether the reversal potentials for sodium and potassium, ENa and EK, whose experimental values are respectively around +50 and -80 mV, minimize or maximize any simple combination of: (a) metabolic energy consumption during an action potential; (b) metabolic energy consumption during quiescence; (c) action potential velocity; (d) maximum firing frequency; and (e) the “energy efficiency” of the action potentials, which is the proportion of the metabolic energy associated with them that actually contributes to net inward or outward currents. None of these quantities, nor any algebraically simple combination of them, has a maximum or minimum over the range of {ENa, EK} parameter space that we investigated. However, there are many functions for which the potassium reversal potential alone has an optimal value. Further analysis reveals that there are three basic underlying optimizations involving EK. The velocity of action potentials is maximized for a value of EK in the experimental range (Fig. ​(Fig.1),1), and the product of the metabolic energy consumption during an action potential and at rest is minimized. The third optimization is for the ratio of action potential energy and maximum firing frequency, which is maximized for biological EK. The interpretation of this optimization may be clear only in the context of the larger squid escape-jet system. Figure 1 The velocity of action potentials (vAP) in the Hodgkin-Huxley model of the squid giant axon as a function of the potassium reversal potential (EK), with the sodium reversal potential (ENa) held fixed at various values. In all cases, vAP attains a maximum ...

Sequential Isotopic Signature Along Gladius Highlights Contrasted Individual Foraging Strategies of Jumbo Squid (Dosidicus gigas)

BackgroundCephalopods play a major role in marine ecosystems, but knowledge of their feeding ecology is limited. In particular, intra- and inter-individual variations in their use of resources has not been adequatly explored, although there is growing evidence that individual organisms can vary considerably in the way they use their habitats and resources.Methodology/Principal FindingsUsing δ13C and δ15N values of serially sampled gladius (an archival tissue), we examined high resolution variations in the trophic niche of five large (>60 cm mantle length) jumbo squids (Dosidicus gigas) that were collected off the coast of Peru. We report the first evidence of large inter-individual differences in jumbo squid foraging strategies with no systematic increase of trophic level with size. Overall, gladius δ13C values indicated one or several migrations through the squid's lifetime (∼8–9 months), during which δ15N values also fluctuated (range: 1 to 5‰). One individual showed an unexpected terminal 4.6‰ δ15N decrease (more than one trophic level), thus indicating a shift from higher- to lower-trophic level prey at that time. The data illustrate the high diversity of prey types and foraging histories of this species at the individual level.Conclusions/SignificanceThe isotopic signature of gladii proved to be a powerful tool to depict high resolution and ontogenic variations in individual foraging strategies of squids, thus complementing traditional information offered by stomach content analysis and stable isotopes on metabolically active tissues. The observed differences in life history strategies highlight the high degree of plasticity of the jumbo squid and its high potential to adapt to environmental changes.

Temporal and ontogenetic variation in the diet of squid (Loligo forbesii Streenstrup) in Scottish waters

The squid Loligo forbesii is the only cephalopod species currently targeted by fisheries in the northern NE Atlantic. An active predator, it feeds primarily on fish, crustaceans and cephalopods. During 15 years since the only previous large-scale study of the diet of this species in Scottish waters, there have been substantial changes in marine fish abundances. The present study evaluates sources of variation (temporal, ontogenetic) in diet composition and prey size preferences of L. forbesii, including a comparison of contemporary (July 2006–June 2007) and historical (1990–1992) dietary datasets. Results revealed significant size-related and seasonal variation in diet composition and prey size. Teleost fish of the families Ammodytidae and Gobiidae were eaten by squid of all sampled sizes, although occurrence of gobies was generally more frequent in smaller squids, while Gadidae were eaten more frequently by larger squids. Cannibalism was also more frequent in larger squids. Compared to the 1990–1992 dataset, clupeid fish were less important in the diet of squid in 2006–2007, while the importance of gobies increased, and the size of gobies eaten also increased. The trend in gadoids differed according to the index used: their frequency of occurrence was considerably higher in 2006–2007 than in 1990–1992, but their numerical importance was slightly lower. In general, results provided little evidence that changes in the diet of L. forbesii correspond with changes in fish abundance, at least at the scales at which these are measured.