In this experimental study the patterns in early marine biofouling communities and possible implications for surveillance and environmental management were explored using metabarcoding, viz. 18S ribosomal RNA gene barcoding in combination with high-throughput sequencing. The community structure of eukaryotic assemblages and the patterns of initial succession were assessed from settlement plates deployed in a busy port for one, five and 15 days. The metabarcoding results were verified with traditional morphological identification of taxa from selected experimental plates. Metabarcoding analysis identified > 400 taxa at a comparatively low taxonomic level and morphological analysis resulted in the detection of 25 taxa at varying levels of resolution. Despite the differences in resolution, data from both methods were consistent at high taxonomic levels and similar patterns in community shifts were observed. A high percentage of sequences belonging to genera known to contain non-indigenous species (NIS) were detected after exposure for only one day.
The primary objective of the population management plan for New Zealand sea lions,
Phocarctos hookeri, is to move the species from its current conservation status of
‘Threatened’ to ‘Non-threatened’. The mechanism by which this will occur is through the
establishment of new breeding colonies away from the only existing colonies at Auckland
Islands and Campbell Island. Otago, on the southeast coast of the South Island of New
Zealand, is one of only three locations where breeding has been recorded away from these
islands in modern times. We found only one female at the initiation of our surveys here in
1991, an individual that had been tagged as a pup at Auckland Islands. This female has
remained resident at Otago and is now breeding. Her first live birth, in the 1993/94 breeding
season, represented the first record of a P. hookeri pup on the New Zealand mainland since
the elimination of the species here by humans c. 150 years ago. Up to and including the
2000/01 breeding season she had produced six pups. Her surviving pups have remained at
Otago and her eldest two daughters have started breeding, producing a further three pups.
From this total of nine live births, two pups have died. Although 6 - 8 other migrant females
have been recorded, to our knowledge none have bred at Otago. We conclude that the
initiation of breeding by P. hookeri at Otago has been a serendipitous event attributable to
atypical behaviour by a single female.
We examined the response of four species of New Zealand marine algae (Ecklonia radiata, Apophlaea lyallii, Rhodymenia spp., Ulva lactuca) and a sea urchin (Evechinus chloroticus) to spatial variation in ultraviolet radiation (UV-R) by examining the concentration of UV-R absorbing compounds known as mycosporine-like amino acids (MAAs). The purpose was to understand how, and the degree to which, local marine species could potentially respond to any future increases in incident UV-R in the New Zealand marine environment. The research was undertaken in Doubtful Sound, where we observed a gradient of water column UV-R transmission along the 40 km length of the fiord. We examined spatial differences in MAAs along the UV-B gradient in the macrophytes and temporal changes in MAAs in sea urchin gonads. Among the algae, thallus MAA concentrations (nmol mg -1 protein) ranged from 12.5 to 87.8 in E. radiata, from 433.1 to 1446.4 in A. lyallii, 12.7 Rhodymenia spp., but were not detected in U. lactuca. For E. chloroticus, gonadal MAA concentrations ranged from 83.9 to 224.3 nmol mg -1 protein spatially, and over the year from 1.85 to 14.12 nmol mg -1 dry weight (DW) depending on site and gametogenic cycle. Laboratory manipulations indicated that concentrations of MAAs in E. chloroticus gonads and eggs are influenced by diet. MAA concentration could be correlated with UV-B intensities in two of the algal species. E. chloroticus MAA concentrations could also be correlated with UV-B transmission, which we concluded was a reflection of the greater ingestion and accumulation of MAArich macrophytes at those sites where higher ambient UV-R induced greater MAA concentrations to occur in the algae. Given this, we suggest that one response of marine species to increases in UV-B would be an increase in the synthesis and/or accumulation of MAAs for photoautotrophs and a dietary accumulation of those MAAs in E. chloroticus, an important herbivore in this system.
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