Species richness in North Atlantic fish: Process concealed by pattern


Henrik Gislason, Technical University of Denmark
Jeremy Collie, University of Rhode Island
Brian R. MacKenzie, Technical University of Denmark
Anders Nielsen, Technical University of Denmark
Maria de Fatima Borges, Instituto Português do Mar e da Atmosfera
Teresa Bottari, Istituto per le Risorse Biologiche e le Biotecnologie Marine
Corina Chaves, Instituto Português do Mar e da Atmosfera
Andrey V. Dolgov, Knipovich Polar Research Institute of Marine Fisheries and Oceanography
Jakov Dulčić, Institute of Oceanography and Fisheries
Daniel Duplisea, Maurice Lamontagne Institute, Fisheries and Oceans Canada
Heino O. Fock, Thuenen Institute of Sea Fisheries
Didier Gascuel, Université Européenne de Bretagne
Luís Gil de Sola, CSIC-IEO - Instituto Español de Oceanografía
Jan Geert Hiddink, Bangor University
Remment ter Hofstede, Van Oord Dredging and Marine Contractors
Igor Isajlović, Institute of Oceanography and Fisheries
Jónas Páil Jonasson, Marine and Freshwater Research Institute
Ole Jørgensen, Technical University of Denmark
Kristján Kristinsson, Marine and Freshwater Research Institute
Gudrun Marteinsdottir, Haskoli Islands
Hicham Masski, Institut National de Recherche Halieutique
Sanja Matić-Skoko, Institute of Oceanography and Fisheries
Mark R. Payne, Technical University of Denmark
Melita Peharda, Institute of Oceanography and Fisheries
Jakup Reinert, Faroe Marine Research Institute
Jón Sólmundsson, Marine and Freshwater Research Institute
Cristina Silva, Instituto Português do Mar e da Atmosfera
Lilja Stefansdottir, Institut National de Recherche Halieutique
Francisco Velasco, InstitutoEspañol de Oceanografía
Nedo Vrgoč, Institute of Oceanography and Fisheries

Document Type


Date of Original Version



Aim: Previous analyses of marine fish species richness based on presence-absence data have shown changes with latitude and average species size, but little is known about the underlying processes. To elucidate these processes we use metabolic, neutral and descriptive statistical models to analyse how richness responds to maximum species length, fish abundance, temperature, primary production, depth, latitude and longitude, while accounting for differences in species catchability, sampling effort and mesh size. Data: Results from 53,382 bottom trawl hauls representing 50 fish assemblages. Location: The northern Atlantic from Nova Scotia to Guinea. Time period: 1977–2013. Methods: A descriptive generalized additive model was used to identify functional relationships between species richness and potential drivers, after which nonlinear estimation techniques were used to parameterize: (a) a ‘best’ fitting model of species richness built on the functional relationships, (b) an environmental model based on latitude, longitude and depth, and mechanistic models based on (c) metabolic and (d) neutral theory. Results: In the ‘best’ model the number of species observed is a lognormal function of maximum species length. It increases significantly with temperature, primary production, sampling effort, and abundance, and declines with depth and, for small species, with the mesh size in the trawl. The ‘best’ model explains close to 90% of the deviance and the neutral, metabolic and environmental models 89%. In all four models, maximum species length and either temperature or latitude account for more than half of the deviance explained. Main conclusions: The two mechanistic models explain the patterns in demersal fish species richness in the northern Atlantic almost equally well. A better understanding of the underlying drivers is likely to require development of dynamic mechanistic models of richness and size evolution, fit not only to extant distributions, but also to historical environmental conditions and to past speciation and extinction rates.

Publication Title, e.g., Journal

Global Ecology and Biogeography