Size-based approaches to aquatic ecosystems and fisheries science: a symposium in honour of Rob Peters

Abstract

This special issue honours Rob Peters' outstanding contributions to the field of aquatic ecology. It focuses on the size spectrum approach -in which individual organisms, rather than species, are the most basic biological unit -and highlights applications of this approach to fisheries management. The 21 papers in this issue cover three subject areas: (i) the use of size spectra to characterize variation in community structure, (ii) the development of size-based models of ecosystem dynamics to address fisheries questions, and (iii) applications of size-based theory to examine the consequences of variation in predator-prey size relationships, body size -trophic level relationships, and body size -life history relationships. The empirical studies herein demonstrate the utility of size spectra as indicators of population or community structure and for detecting impacts associated with environmental change. Future research focused on refining size-based sampling methods, standardizing metrics and analytical methods, understanding model sensitivity to the underlying assumptions, and comparative studies across ecosystems will enhance our ability to reliably interpret changes in size spectrum characteristics, thus facilitating their use as indicators of ecological change.Résumé : Le présent numéro spécial souligne la contribution exceptionnelle de Rob Peters au domaine de l'écologie aquatique. Il se penche sur l'approche axée sur les spectres de tailles, selon laquelle l'individu, plutôt que l'espèce, constitue l'unité biologique la plus fondamentale, et il présente des applications de cette approche de gestion des pêches. Les vingt et un articles qu'il renferme couvrent trois grands secteurs d'étude, à savoir (i) l'utilisation des spectres de tailles pour caractériser les variations de la structure de communautés, (ii) le développement de modèles basés sur la taille de la dynamique des écosystèmes pour examiner des questions touchant aux ressources halieutiques, et (iii) des applications de la théorie basée sur la taille pour examiner les conséquences des variations des relations de la taille des prédateurs et proies, des relations entre la taille du corps et le niveau trophique et des relations entre la taille du corps et le cycle biologique. Les études empiriques présentées démontrent l'utilité des spectres de tailles comme indicateurs de la structure des populations ou des communautés et pour détecter les impacts associés aux modifications de l'environnement. Des travaux de recherche futurs visant le raffinement des méthodes d'échantillonnage basées sur la taille, la normalisation des paramètres et méthodes analytiques, la compréhension de la sensibilité des modèles aux hypothèses sous-jacentes et des études comparatives de différents écosystèmes accroîtront la capacité d'interpréter de manière fiable les variations des caractéristiques des spectres de tailles, en facilitant ainsi l'utilisation comme indicateurs de changements écologiques. [Traduit par la Rédaction]

Modelling the community size-spectrum: recent developments and new directions

“…Therefore, compromises are necessary in order to keep models' complexity and associated uncertainties in a manageable domain, finding a sweet spot between over simplification and over excessive complexity (Collie et al, 2016). Among the variety of marine ecosystem models, size-spectrum models appear as a promising alternative for such ecosystem-based approach (Jennings and Brander, 2010;Giacomini et al, 2016). Sheldon et al (1972) first made the observation that ecosystem biomass remains approximately constant when summed within logarithmically equal body mass intervals, from bacteria to whales.…”

Body size–trophic position relationships among fishes of the lower Mekong basin

“…Tropical rivers support the highest freshwater fish diversity, and many have high productivity that supports important fisheries. Therefore, a better understanding of the relationship between body size and TP in these ecosystems has immediate resource management applications [ 23 , 24 ].…”

“…Given the great ecological diversification apparent among tropical freshwater fishes, we predicted the body size–TP relationship in tributaries of the Lower Mekong would be influenced by multiple traits rather than only gape limitation. Better understanding of body size–TP relationships in local assemblages is critical for numerous ecological applications that are based on community size spectra [ 23 ].…”

Isometric growth in the world's largest bony fishes (genus Mola)? Morphological insights from fisheries bycatch data

“…It is worth noting that a degree of individual variation is apparent in the data, such as in the mass/length relationship among larger specimens, but this may occur as a function of body condition or reproductive efforts. As the ability to accurately predict multiple measurements can provide baseline data for fisheries modeling, including size‐based models (see review: Giacomini et al, ), mass‐length analysis (e.g.,Murphy et al, ; Blackwell et al, ; Froese, ), mass balance models (e.g.,Vasconcellos et al, ; Jarre‐Teichmann, ) and estimation of fish trophic level (e.g.,Dickie et al, ; Jennings et al, ), the results of the linear models described here may be of considerable use to fisheries scientists, enabling estimation of 16 traits from a single measurement. Without routine collection of sunfish data, we cannot progress to consider the size frequency of populations; however, these data present a baseline for such efforts.…”