Robin N Gibson

Flatfishes: biology and exploitation.

Series Foreword. Preface. Acknowledgements. List of Contributors. 1. Introduction (Robin N. Gibson). 1.1 The fascination of flatfishes. 1.2 A brief history of flatfish research and its contribution to fish biology and fisheries science. 1.3 Scope and contents of the book. 1.4 Nomenclature. Acknowledgements. References. 2. Systematic diversity of the Pleuronectiformes (Thomas A. Munroe). 2.1 Introduction. 2.2 Systematic profile of the Pleuronectiformes. 2.3 Intrarelationships of the Pleuronectiformes. 2.4 Brief synopses of the suborders and families. 2.5 Diversity of the Pleuronectiformes. 2.6 Patterns of species diversity among pleuronectiform families. 2.7 Conclusions. Acknowledgements. References. 3. Distributions and biogeography (Thomas A. Munroe). 3.1 Introduction. 3.2 Geographic distribution of pleuronectiform lineages. 3.3 Global patterns of species richness for the Pleuronectiformes. 3.4 Species richness in specific environments. 3.5 Historical biogeography. 4. Ecology of reproduction (A.D. Rijnsdorp and P.R. Witthames). 4.1 Introduction. 4.2 Spawning. 4.3 Gonad development. 4.4 Age and size at first maturation. 4.5 Energetics. 4.6 Contaminants and reproduction. 5. The planktonic stages of flatfishes: physical and biological interactions in transport processes (Kevin. M. Bailey, Hideaki Nakata and Henk W. van der Veer). 5.1 Introduction: the problem. 5.2 Flatfish eggs and larvae in the plankton: variations in form and function, time and space. 5.3 Physical mechanisms of transport and retention. 5.4 Adaptations to transport conditions: geographical and species comparisons. 5.5 Transport and population biology. 6. Recruitment (Henk W. van der Veer and William C. Leggett). 6.1 Introduction. 6.2 Range of distribution. 6.3 Average recruitment levels. 6.4 Recruitment variability. 7. Age and growth (Richard D.M. Nash and Audrey J. Geffen). 7.1 Introduction. 7.2 Age estimation. 7.3 Growth of larvae. 7.4 Growth during metamorphosis. 7.5 Growth on nursery grounds. 7.6 Growth of adults. 7.7 Longevity. 8. Ecology of the juvenile and adult stages of flatfishes: distribution and dynamics of habitat associations (Kenneth.W. Able, Melisssa Neuman and Hakan Wennhage). 8.1 Introduction. 8.2 Definitions. 8.3 Distribution and ontogeny. 8.4 Future emphasis. 9. The trophic ecology of flatfishes (Jason S. Link, Michael J. Fogarty and Richard W. Langton). 9.1 Introduction. 9.2 Major flatfish feeding groups. 9.3 Flatfish predators. 9.4 Flatfish competitors. 9.5 Flatfish trophic dynamics: a case study of Georges Bank. 9.6 Summary and conclusions. 10. Behaviour of flatfishes (Robin N. Gibson). 10.1 Introduction. 10.2 Locomotion and related behaviour. 10.3 Colour change. 10.4 Reproduction. 10.5 Feeding. 10.6 Predation and reactions to predators. 10.7 Movements, migrations and rhythms. 10.8 Behaviour in relation to fishing, aquaculture and stock enhancement. 11. Atlantic flatfish fisheries (Richard Millner, StephenJ. Walsh and Juan M. Diaz de Astarloa). 11.1 Introduction. 11.2 Main species and nature of the fisheries. 11.3 History of exploitation. 11.4 Economic importance. 11.5 Management. 12. Pacific flatfish fisheries (Thomas Wilderbuer, Bruce Leaman,, Chang Ik Zhang, Jeff Fargo and Larry Paul). 12.1 Introduction. 12.2 Main species and nature of the fisheries. 12.3 History of exploitation. 12.4 Economic importance. 12.5 Management. 13. Tropical flatfish fisheries (Thomas A. Munroe). 13.1 Introduction. 13.2 Main species and nature of the fisheries. 13.3 History of exploitation. 13.4 Economic importance. 13.5 Management and conservation. 14. Assessment and management of flatfish stocks (Jake Rice, Steven X. Cadrin and William G. Clarke). 14.1 Concepts and terms. 14.2 Population dynamics, assessment and management. 14.3 Assessment and management summary. 14.4 Conclusions. 15. Aquaculture and stock enhancement (B.R. Howell and Y. Yamashita). 15.1 Introduction. 15.2 Hatchery production of larvae and juveniles. 15.3 Intensive farming. 15.4 Stock enhancement. 15.5 Conclusions. Appendix 1. Appendix 2. Index of scientific and common names. Subject index.

Behaviour and the distribution of flatfishes

Abstract The paper reviews the changes in distribution that take place during the development of flatfishes from the egg to the adult. It describes the behaviour patterns involved in changing habitats, particularly the use of vertical migration to take advantage of tidal currents to aid transport, and the controlling mechanisms underlying these behaviour patterns. The discussion of mechanisms concentrates on the role of possible external (light, temperature, salinity, currents and pressure) and internal (endogenous rhythms, physiological state) cues used to time movements. It also considers the likely clues for directing movement (mainly environmental gradients) and for recognising destinations (food, conspecifics, chemical characteristics, substratum type). Finally, the role of learning in flatfish movement patterns is briefly discussed.

TEMPORAL PATTERNS OF MOVEMENT IN JUVENILE FLATFISHES AND THEIR PREDATORS - UNDERWATER TELEVISION OBSERVATIONS

Underwater television cameras were used to observe the movements of bottom-living animals in the intertidal and shallow subtidal zones of a sandy shore over sixteen 24-h periods in the summers of (1991) and (1992). Juvenile (O-group) flatfishes, predominantly Pleuronectes platessa L. with some Limanda limanda (L.), were only seen moving on the bottom by day, with most observed at high water and just before sunset. Their movements were directed offshore in the morning and onshore in the afternoon. They also tended to move onshore with the flood tide and offshore with the ebb. These fishes may use midwater swimming for intertidal migration by night because none was seen moving on the bottom at night. Potential predators of O-group flatfishes, cod Gadus morhua L., crab Carcinus maenas (L.) and the brown shrimp Crangon crangon (L.), were most often seen moving on the bottom at night. Crangon, Carcinus and I-group flatfishes were seen in similar numbers in the subtidal and intertidal zones, while O-group flat-fishes, cod and hermit crabs Pagurus bernhardus (L.) were seen much more frequently under the subtidal camera.

The Behavioural Basis of Predator-Prey Size Relationships Between Shrimp ( Crangon Crangon ) and Juvenile Plaice ( Pleuronectes Platessa )

The shrimp, Crangon crangon (L.) (Crustacea: Crangonidae), is a significant predator of the smallest sizes of plaice, Pleuronectes platessa L. (Teleostei: Pleuronectidae), during and immediately after the fish settle on sandy beaches when predation rate is strongly dependent on the size of both the predator and the prey. Laboratory experiments showed that this size-dependency is caused principally by the superior escape capabilities of larger fish once captured rather than differences in the ability of different sizes of shrimps to capture their prey. Fish that escape after capture are often wounded and some of these wounds may subsequently be fatal. Many shrimps capture and eat fish that are larger than their stomach volume resulting in long handling times and low prey profitabilities. For all sizes of shrimps used (36–65 mm total length) prey profitability (mg prey ingested min −1 ) increases with decreasing fish length.

A comparison of predatory behaviour in flatfish

Abstract The feeding behaviour of six species of flatfish was examined. Four species of bothids showed very different hunting tactics when feeding on mysids. Seventy per cent of attacks by turbot ( Scophthalmus maximus ) occurred in the water column, compared with only 6% for brill ( Scophthalmus rhombus ), whilst the topknots Zeugopterus punctatus and Phrynorhombus regius always remained in contact with the substratum. The turbot were agile and rapidly pursued their prey, brill slowly stalked their prey and the topknots employed a ‘sit and wait’ strategy. When feeding on shrimps, turbot made 90% of their attacks from the substratum. Plaice ( Pleuronectes platessa ) feeding on live worms, exhibited less complex behaviour sequences than the bothids. All hunting occurred on the substratum and consisted of short sequences of a ‘browsing’ type of predation. When offered more mobile prey ( Corophium sp.) plaice did not display the agility nor the complex hunting tactics shown by the bothid species. The simplest feeding behaviour was shown by the sole ( Solea solea ) when feeding on worms and this simplicity is probably related to its olfactory/tactile method of prey location.

The effect of prey type on the predatory behaviour of the fifteen-spined stickleback, Spinachia spinachia (L.)

Abstract The fifteen-spined stickleback, preying on the mysid, Neomysis integer , and the amphipod, Gammarus locusta , maximized its energy intake by adjusting its predatory behaviour to the prey being attacked. The escape speed of Neomysis placed an upper constraint on the size of the prey available to fish of a given size. The increase in importance of Neomysis in the natural diet of larger sticklebacks reflected size-dependent limitations of the fast-start performance in these fish. The escape speed of Gammarus did not limit its availability to the sticklebacks; the limiting factor for this prey was its cross-sectional area. The fish expended 20 times more energy attacking Neomysis than Gammarus , but Gammarus took up to 159 times longer to ingest. Neomysis always responded to an attack with a tail-flip, which usually resulted in movement at an angle of approximately 90° to the direction of attack. Although Gammarus occasionally used a tail-flip response, it was never used to escape a fish attack. Adoption of a stationary C-shape often deterred the fish from attacking Gammarus .

Are digestive characteristics important contributors to the profitability of prey

SummaryIn the field, Spinachia fed on four types of prey; copepods, isopods, mysids and amphipods. As fish size increased, mysids gradually succeeded amphipods as the most important food type in the diet. Prey dimensions and morphometry of the fishs mouth most accurately predicted capture efficiency for amphipods, whereas for mysids capture efficiency was determined by the preys escape response and the fishs fast-start capability. Responses to model prey revealed the ability of fish to differentiate among contrasting prey characteristics, resulting in the adoption of appropriate predatory tactics. Amphipods were associated with a shorter gut evacuation time than mysids, although approximately equal proportions of energy were absorbed from each. Similar rations of mysids and amphipods were required to satiate fish. The lower energy content per unit dry mass of amphipods was off set by their lower water content. From pre-digestive behaviour, we predicted that mysids were more profitable than amphipods, and this was reflected in the fishs choice. Conversely, incorporating the net rate of energy uptake by the gut led us to predict that amphipods were more profitable. Although physiological constraints clearly influence the net rate of energy uptake, it appears that dietary preferences are based on pre-digestive predatory behaviour and hence on time minimisation.

Use of cues by Lipophrys pholis L. (Teleostei, Blenniidae) in learning the position of a refuge

The ability of Lipophrys pholis to remember the position of a refuge was tested in an artificial habitat under the influence of different visual clues. L. pholis learned the position of the refuge in the presence of a clue consisting only of a small black screen. They responded to this clue by moving towards it and pressing themselves up against it. Lego towers and a white screen clue did not provoke such a response. In a further experiment L. pholis continued to respond to the black screen in this way when the screen was moved to another location further from the refuge. After 12 days L. pholis learned to use the black screen in its new position as an indirect clue and navigate to the refuge directly without first approaching the black screen. These results suggested that when placed in a novel habitat the immediate reaction of L. pholis is to move quickly towards the first dark area they see but, with experience, they can use the position of large objects around them to navigate quickly and efficiently to a refuge.

The effect of prey shape on the predatory behaviour of the common shore crab, Carcinus maenas (L.)

Crabs used a limited repertoire of behaviours when attacking resistant prey. Crushing and rotating were the most commonly used behaviours with all prey types. Other behaviours, such as sawing, biting and poking became more important in prolonged predatory acts. The duration of crushing attempts became longer as prey size increased. Crabs were able to improve their handling efficiency, the frequency, but not the duration, of behaviours decreased with experience. Crabs were able to subtly alter their predatory behaviour, within and between predatory acts. Presumably the ability to fine tune predatory behaviour according to prey characteristics, coupled with the ability to learn appropriate handling techniques, leads to more efficient predatory behaviour.