Henry S Carson

Washington Department of Fish & Wildlife | WDFW · Fish Program

Declines in abalone populations throughout the world have led to conservation measures including fishery closures and captive breeding programs aimed at stock restoration. Restoration of endangered pinto abalone (Haliotis kamtschatkana) in the southern Salish Sea (Washington State, USA) began in the mid-2000s, and since 2009, nearly 40,000 hatchery...

The commercial fishery for subtidal Pacific geoduck clams (Panopea generosa) in Washington State, USA, is substantial both by the amount of biomass extracted (2 million kg in 2019) and by the economic value (US $50 million annual). Management for this fishery, which began in 1970, is challenged by this species’ long lives, cryptic behavior, and rec...

• Wild populations of pinto abalone (Haliotis kamtschatkana) in Washington State have declined by 97% since 1992, despite a fishery closure since 1994. No recruitment has been detected recently, indicating probable reproductive failure due to low densities. A pilot programme placed a total of over 11,000 hatchery‐origin juveniles, age 18–22 months,...

Size, growth, and density have been studied for North American Pacific coast sea urchins Strongylocentrotus purpuratus, S. droebachiensis, S. polyacanthus, Mesocentrotus (Strongylocentrotus) franciscanus, Lytechinus pictus, Centrostephanus coronatus, and Arbacia stellata by various workers at diverse sites and for varying lengths of time from 1956...

Plastic pollution is ubiquitous throughout the marine environment, yet estimates of the global abundance and weight of floating plastics have lacked data, particularly from the Southern Hemisphere and remote regions. Here we report an estimate of the total number of plastic particles and their weight floating in the world’s oceans from 24 expeditio...

Plastic and other anthropogenic debris (e.g., rubber, tar) augment natural floating substrates (e.g., algal rafts, pumice) in the open ocean, allowing "islands" of substrate-associated organisms to persist in an otherwise unsuitable habitat. We examined a total of 242 debris objects collected in the eastern Pacific in 2009 and 2011 (32-39A degrees...

Microorganisms likely mediate processes affecting the fate and impacts of marine plastic pollution, including degradation, chemical adsorption, and colonization or ingestion by macroorganisms. We investigated the relationship between plastic-associated microorganism communities and factors such as location, temperature, salinity, plankton abundance...

One of the primary threats to ocean ecosystems from plastic pollution is ingestion by marine organisms. Well-documented in seabirds, turtles, and marine mammals, ingestion by fish and sharks has received less attention until recently. We suggest that fishes of a variety of sizes attack drifting plastic with high frequency, as evidenced by the appar...

Geochemical signatures of early life stages are increasingly used to study population connectivity. This approach utilizes spatial variability in chemical signatures to predict natal or nursery origins of post-dispersal individuals by comparison with a chemical reference atlas created from individuals of known origin. To examine the relative import...

The exchange of individuals among habitat patches (connectivity) has broad relevance for the conservation and management of marine metapopulations. Elemental fingerprinting-based research conducted over the past 12 years along the open coastline and bays of San Diego County in southern California evaluated connectivity patterns for seven species: o...

Recently researchers have gone to great lengths to measure marine metapopulation connectivity via tagging, genetic, and trace-elemental fingerprinting studies. These empirical estimates of larval dispersal are key to assessing the significance of metapopulation connectivity within a demographic context, but the life-history data required to do this...

We investigated the physical properties of beaches contaminated with plastic fragments. We compared sediment cores from Hawai'i Island's Kamilo Beach, notable for plastic accumulation, to cores from a nearby beach. Compared to the nearby beach, Kamilo sediments contained more plastics (up to 30.2% by weight), were coarser-grained, and were more per...

Populations of most marine organisms are connected by the dispersal of larval stages, with profound implications for marine conservation. Because of the extreme effort needed to empirically measure larval exchange, multispecies conservation efforts must estimate connectivity by extrapolation using taxonomy, adult distribution, life history, behavio...

The Olympia oyster is a useful model to study the population connectivity of estuarine invertebrates because it incorporates chemical information about the natal site into its shell before dispersal. This information can be accessed in recruits using laser ablation inductively coupled plasma mass spectrometry and compared with predispersal shells f...

Chemical fingerprinting techniques recently have been used to track larval dispersal of estuarine species that bear calcified structures, but the applicability of this important approach may be limited on the open coast where chemical signatures may be less distinctive and for the many species that do not retain calcified structures throughout deve...

Using known and inferred life-history information, we estimated the dispersal potential of 501 polychaete species sampled during a 1998 monitoring study in the Southern California Bight. We tested the hypothesis that species having life-history traits that suggest long-distance dispersal will be encountered more frequently throughout the region tha...