Ecosystem Health

Harbor seals are an important apex predator, feeding on a diverse range of fish and invertebrates in nearshore waters including herrings, sardines, hake, flounder, sole, octopus, squid and crabs. Harbor seals spend about half of their time hauled out resting, sunning, reproduction, and interacting socially. Haul-outs can be in any coastal habitat and are locations suitable for assessing seal populations and role of local and regional disturbance in seal abundance.

Planktivorous fish (fish that eat plankton) abundance and size structure are indicative of the ability of the ecosystem to capture nutrients provided by the influx of plankton. These could b species that specialize in plankton, or juvenile stages of other species that eat plankton.

Focus species: Blue rockfish

The presence and increased abundance of predators indicates well-being in other trophic levels. Within kelp ecosystems, piscivorous fish may also play key ecological roles in moderating food web structure through top-down control. Certain fish are targeted by recreational and commercial anglers and well-being of populations of these species will provide social and economic benefits to coastal communities. Abundance and population structure (size classes) are important metrics for this indicator. Focal species include: Various rockfish, lingcod, cabezon, bocaccio, leopard shark, and bat ray

Resident and migratory birds forage in soft-sediment and rocky-intertidal ecosystems on a wide range of fish and invertebrate species. Populations of these birds can vary with climatic and oceanographic conditions as well as availability of prey in intertidal systems. Diversity of species and abundance of species are both important metrics.

Focal species: black oystercatchers, Brandt's cormorant, pelagic cormorant, pigeon guillemot, and common murre

As in many ecosystems, in soft-bottom habitats, predators may play an important role in structuring animal communities. The density and size structure of focal predator species can indicate health of other trophic levels. The benthic invertebrates referred to here are those with a strong association with the substrate and may be subject to fishing pressure. Focal species: Dungeness crab and sea star

Predators can play an important role in structuring community composition within ecosystems. Abundance and size structure of a range of fish species can provide information about the health of multiple trophic levels. Demersal fish are those with a strong association with the substrate. Many of these species may be subject to strong fishing pressure. Focal species: California halibut, starry flounder, and sanddab

Fish species vary in their reproductive strategies, from live birthing (e.g., certain sharks) to targeted release of gametes (e.g., salmon). Most larval fish stages must feed by the time their yolk is depleted. Availability of prey, climatic/oceanographic conditions, predation, stranding, pollution, and various natural & artificial disturbance can affect larval stages and thus recruitment of young into the juvenile-adult population. Although recruitment rates will naturally vary, measuring trends in rate for individual or many species across years or decades will provide important information about coastal ecosystem health.

Marine invertebrates vary in their reproductive strategies, from brooding until settlement to broadcast spawning of gametes and from direct developing (non-feeding) forms to long-lived larval stages. Regardless of strategy, recruitment rates into existing or new habitat can determine survival of a species and adaptation to new conditions. Recruitment can be measured as successful settling or juvenile stages into appropriate habitat for the juvenile and/or adult form.

Near-shore shallow-water habitats are home to a range of fish species, including juveniles that seek refuge from predators in open water as well as resident species that forage in the surf zone on fish and invertebrate prey. Surfperch play a major link in trophic transfer in the near-shore: their diet consists of isopods, amphipods, copepods, molluscs, and polychaete worms. They in turn are prey for larger fish, such as kelp bass, California halibut, sturgeon, rockfish and salmon, as well as harbor seals and birds. Surfperch and surf smelt are both subject to fishing pressure and surfperch may be in decline in California. Focal species: Surfperch and surf smelt

Suspension feeders play an important role in ecosystems, converting phytoplankton to biomass and, as prey, providing energy available to higher trophic levels. Presence of sand crabs indicates a beach with sufficient nutrient inputs and size of the beach populations may be related to near-shore richness. Sand crab populations are generally robust and may vary with climatic and oceanographic conditions. Razor clams are one of thelongest-lived organisms in the sandy intertidal so they may integrate ecosystem conditions over long time-frames. Focal species: sand crabs and razor clams