Discerning the Management-Relevant Ecology and Distribution of Sea Pens (Cnidaria: Pennatulacea) in Norway and Beyond

Rebecca E Ross,Pål Buhl-Mortensen,Genoveva Gonzalez-Mirelis,Pablo Lozano

doi:10.3389/fmars.2021.652540

Rebecca E Ross, Pål Buhl-Mortensen + Show 2 more

Open Access

https://doi.org/10.3389/fmars.2021.652540

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Abstract

Sea pens are considered to be of conservation relevance according to multiple international legislations and agreements. Consequently, any information about their ecology and distribution should be of use to management decision makers. This study aims to provide such information about six taxa of sea pen in Norwegian waters [Funiculina quadrangularis (Pallas, 1766), Halipteris spp., Kophobelemnon stelliferum (Müller, 1776), Pennatulidae spp., Umbellula spp., and Virgulariidae spp.]. Data exploration techniques and ensembled species distribution modelling (SDM) are applied to video observations obtained by the MAREANO project between 2006 and 2020. Norway-based ecological profiles and predicted distributions are provided and discussed. External validations and uncertainty metrics highlight model weaknesses (overfitting, limited training/external observations) and consistencies relevant to marine management. Comparison to international literature further identifies globally relevant findings: (a) disparities in the environmental profile of F. quadrangularis suggest differing “realised niches” in different locations, potentially highlighting this taxon as particularly vulnerable to impact, (b) none of the six sea pen taxa were found to consistently co-occur, instead partially overlapping environmental profiles suggests that grouping taxa as “sea pens and burrowing megafauna” should be done with caution post-analyses only, (c) higher taxonomic level groupings, while sometimes necessary due to identification issues, result in poorer quality predictive models and may mask the occurrence of rarer species. Community-based groupings are therefore preferable due to confirmed shared ecological niches while greater value should be placed on accurate species ID to support management efforts.

Highlights

Responsible management of worldwide marine resources requires an understanding of the distribution and ecology of vulnerable marine species and habitats across management areas (Crowder and Norse, 2008)
As many sea pen taxa live in soft sediments on continental shelves, these species and the habitats they form are likely to be impacted by bottom fisheries
In particular we focus on: (a) whether we can predict the distribution of these taxa accurately enough to aid marine management in Norway (b) whether there are any disparities between the environmental profiles in different countries, and what this might mean from the perspective of management decision-making internationally, (c) whether a grouping as “sea pens and burrowing megafauna communities” is useful at the analysis stage, or if taxa should be treated more individually, and (d) whether there are management implications where there are taxonomic identification issues

Summary

Introduction

Responsible management of worldwide marine resources requires an understanding of the distribution and ecology of vulnerable marine species and habitats across management areas (Crowder and Norse, 2008). This requires identification of both the vulnerable species or habitat and a management-relevant interpretation of ecological and distributional information. As many sea pen taxa live in soft sediments on continental shelves, these species and the habitats they form are likely to be impacted by bottom fisheries. Sea pen species and habitats are often included on lists of habitats for conservation management action (e.g., OSPAR, 2010; ICES, 2020)

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