Relative predation risk in two types of habitat for juvenile Australasian spiny lobsters, Jasus edwardsii

ABSTRACT

The decline in kelp habitat on coastal reefs resulting from changes in ocean climate and the distribution and abundance of herbivorous species is common in many temperate regions of the world. Kelp habitat is highly productive, biodiverse and provides a complex habitat into which many organisms recruit, including spiny lobsters, such as the Australasian red spiny lobster, Jasus edwardsii. The displacement of kelp habitat by less-complex barren reef habitat has the potential to influence the risk of predation for early juvenile lobsters. Therefore, relative predation risk on the juvenile spiny lobster, J. edwardsii, was compared for kelp and barren habitats on the northeast coast of New Zealand using juvenile lobsters held in transparent containers and recording predators with a video recorder. In total, 188 predation attempts were observed within 420 h of video recordings gathered over 3 weeks of sampling. There was an overall higher predation risk in barren habitats. Daytime predation attempts were higher in barren compared to kelp habitat; however, there was no difference between the habitats for night time, dawn or dusk observations, when juvenile lobsters are emergent from shelters and vulnerable to predation. Similar numbers of predatory species were identified in kelp (13) and barren habitat (12). Other factors, such as food availability and time spent away from shelter, especially during night and crepuscular periods, need consideration in future studies when investigating the cause of differences in juvenile lobster mortality among habitats.

RESPONSIBLE EDITOR:

• Roy Kropp

KEYWORDS:

• Habitat change
• juvenile lobster
• survival

Acknowledgements

We thank the staff and students of the Leigh Marine Laboratory for helping with the field work, especially Brady Doak and Arthur Cozens for assistance with boating operations and John Atkins for assistance with camera systems. Thanks also to Mark Wilcox and Leonardo Zamora for substantial help in the field. This research was conducted with approval R236 and R930 under New Zealand’s Animal Welfare Act 1999.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Andrew G. Jeffs http://orcid.org/0000-0002-8504-1949