Do predators, handling stress or field acclimation periods influence the survivorship of hatchery-reared abalone Haliotis kamtschatkana outplanted into natural habitats?

Published source details Hansen S.C. & Gosselin L.A. (2013) Do predators, handling stress or field acclimation periods influence the survivorship of hatchery-reared abalone Haliotis kamtschatkana outplanted into natural habitats?. Aquatic Conservation: Marine and Freshwater Ecosystems, 23, 246-253.
Share Tweet Email

Actions

This study is summarised as evidence for the following.

	Action	Category
	Transplant/release captive-bred or hatchery-reared species in predator exclusion cages Action Link
	Transplant/release captive-bred or hatchery-reared species - Transplant/release molluscs Action Link

Transplant/release captive-bred or hatchery-reared species in predator exclusion cages

A replicated, controlled study in 2009 in one area of seabed off Vancouver Island, North Pacific Ocean, Canada (Hansen & Gosselin 2013) found that hatchery-reared northern abalone Haliotis kamtschatkana transplanted into the wild in predator exclusion cages did not have higher survivorship following release compared to those transplanted directly onto the seabed. For the first seven days after transplantation, abalone in predator cages (not yet released) had higher survivorship (96%) than those not transplanted in cages (57%). However, seven days after being released from their cages, survivorship of abalone had decreased (42%) and was similar to those directly transplanted onto the seabed (34%). In addition, transplanting abalone in cages 1 m above the seabed or in cages onto the seabed led to similar survivorship, both before release (after 7 days; 96% vs 96%) and after release (after 14 days; 38% vs 46%). In 2009 a total of 1,680 hatchery-raised abalone (4.2–6.5 cm shell length) were used in a project assessing the survivorship of transplanted abalone. Three groups of 20 tagged abalone were transplanted at each of seven locations 10 m apart (9 m water depth). Each group corresponded to one of three treatments: 1) abalone placed in predator exclusion cages suspended 1 m above the seabed, 2) abalone placed in predator exclusion cages onto the seabed, 3) abalone transplanted directly onto the seabed (no cage). Seven days after transplanting, abalone in predator exclusion cages were released and allowed to disperse. On day 7 and 14 following transplanting, surviving abalone were searched for and counted inside all cages and during circular surveys (5 m radius around each of the transplantation locations).

(Summarised by: Anaëlle Lemasson & Laura Pettit)
Transplant/release captive-bred or hatchery-reared species - Transplant/release molluscs

A replicated, controlled study in 2009 in one area of seabed of Vancouver Island, North Pacific Ocean, Canada (Hansen & Gosselin 2013) found that transplanting hatchery-reared northern abalone Haliotis kamtschatkana into the wild reduced survivorship after seven days. Survivorship was lower in transplanted abalones (average survivorship: 0.58) compared to non-transplanted hatchery-reared abalone kept in tanks (average survivorship: 0.97–0.99). In 2009 a total of 1,680 hatchery-raised abalone (4.2–6.5 cm shell length) were used in a project assessing the survivorship of transplanted abalone. Seven groups of 20 tagged abalone were transplanted onto the seabed at 10 m intervals (9 m water depth). Seven days after transplanting, surviving abalone were searched for and counted during circular surveys (5 m radius around each of the transplant locations). Seven groups of 140 abalone were kept in hatchery tanks (not transplanted) for comparison. After seven days, the number of surviving abalone in tanks was determined.

(Summarised by: Anaëlle Lemasson & Laura Pettit)