Seabed Biodiversity Shifts Identify Climate Regimes: The 2011 Climate Regime Shift and Associated Cascades

Using search programs for a long-term SCUBA taxonomic database (3865 dives) for Strait of Georgia seabed sites, 1077 taxa were screened to select rare or highly abundant taxa and to present the data according to climate regime categories. Ocean Niño Index (ONI) climate regime shifts are defined here as the year of the end of the first La Niña closely paired with an El Niño by ≤2 months separation, where anomalies for both El Niño and La Niña exceed 1.0 on the ONI scale. For both rare and abundant taxa, patterns of increased or decreased abundance frequently correspond to years defining climate regimes. Cascading effects of climate regime shifts may occur via changes in community composition. The sea star wasting disease (SSWD) syndrome eliminated urchin predators so that urchins have decreased abundance of a kelp species that is nursery habitat for spot prawns. We conclude that 2011 was a climate regime shift. This 2011 regime shift coincided with loss of 11 seabed species in the Strait of Georgia, none of them at their southern range extreme

Formation, Persistence, and Recovery of Glass Sponge Reefs: A Case Study

Glass sponge reefs (bioherms) are known to occur on glacial deposits but have not previously been observed to develop on fjord bedrock ridges. It is assumed that sexual reproduction dominates reef recruitment and that sedimentation can cover intact sponge skeletons. Over a decade of scuba diving research at a small fjordic bioherm, including installation of bar-coded marker stakes, transplants of loose fragments and survey transects of substrate depth with an avalanche probe have led to new insights into the dynamics of bioherm formation and persistence. We present evidence for recovery of sponge growth from scree slopes of collapsed fragments and logged the temporal changes associated with sponge fragmentation and recovery. Bar-coded stakes were installed in 2014 to enable verification of location and sponge identity through time. Photo documentation of growth, collapse, and regrowth is presented. Research on a sponge garden on glacial sediments reveals that earliest sedimentation may center around prostrate boot sponges and bristly tunicates among the cloud and vase sponges. Although hexactinellid boot sponges do not contribute to the geologic base of bioherms, they may take part as a successional community in the substrate conditioning that could result in the genesis of a glass sponge reef or bioherm

Polygamous mating and high levels of genetic variation in lingcod, Ophiodon elongatus, of the Strait of Georgia, British Columbia. Environmental Biology Fishes 69

Synopsis Lingcod, Ophiodon elongatus, is a nest-guarding marine fish of western North America. Breeding occurs in late winter and early spring after males establish territories and guard nest sites therein. Eggs deposited as clutches in the nest site hatch ∼7 weeks after fertilization. We evaluated the level of genetic variation in lingcod spawning in the central Strait of Georgia through analysis of microsatellite and mitochondrial D-loop variability in fertilized egg samples collected from guarded clutches. Reconstructed parental genotypes displayed a high level of allelic diversity and observed heterozygosity (83-91%) over five microsatellite loci. Progeny of a single clutch were invariably derived from a single mother and between one and five fathers. Multiple egg samples were collected from inside and outside positions on 13 lingcod egg clutches in February 2002. Fin clip samples provided microsatellite genotypes for six of the nine guardian males. Analysis of between 33 and 306 eggs from each clutch indicated that each of the 13 clutches was produced by a different mother and five of them were sired entirely by the attendant male guardian. Eight clutches were sired by multiple males, with neighboring male guardians frequently involved in clutch fertilization. Known guardian males accounted for at least 78% of observed egg fertilization, although non-territorial males were observed and may have participated in spawning. Egg fertilization by individual males was spatially heterogeneous throughout egg clutches. One male guardian failed to fertilize detectable numbers of eggs in his own or any other clutch within the study area and may have been an adoptive father. The polygynous mating structure of lingcod may help maintain genetic variation in the species

Densovirus associated with sea-star wasting disease and mass mortality

Populations of at least 20 asteroid species on the Northeast Pacific Coast have recently experienced an extensive outbreak of sea-star (asteroid) wasting disease (SSWD). The disease leads to behavioral changes, lesions, loss of turgor, limb autotomy, and death characterized by rapid degradation (“melting”). Here, we present evidence from experimental challenge studies and field observations that link the mass mortalities to a densovirus (Parvoviridae). Virus-sized material (i.e., <0.2 μm) from symptomatic tissues that was inoculated into asymptomatic asteroids consistently resulted in SSWD signs whereas animals receiving heat-killed (i.e., control) virus-sized inoculum remained asymptomatic. Viral metagenomic investigations revealed the sea star-associated densovirus (SSaDV) as the most likely candidate virus associated with tissues from symptomatic asteroids. Quantification of SSaDV during transmission trials indicated that progression of SSWD paralleled increased SSaDV load. In field surveys, SSaDV loads were more abundant in symptomatic than in asymptomatic asteroids. SSaDV could be detected in plankton, sediments and in nonasteroid echinoderms, providing a possible mechanism for viral spread. SSaDV was detected in museum specimens of asteroids from 1942, suggesting that it has been present on the North American Pacific Coast for at least 72 y. SSaDV is therefore the most promising candidate disease agent responsible for asteroid mass mortality