There is a growing awareness that large-scale patterns of distribution in marine organisms are often correlated with large-scale ocean dynamics, suggesting that the physical environment strongly influences the dynamics of marine populations. But correlations can be misleading. Our ability to predict population dynamics depends on our understanding of the mechanisms through which individuals are tied to their physical environment, and our knowledge of mechanism is woefully lacking. For example, to accurately assess the efficacy of marine protected areas (MPAs) and other spatial management interventions (e.g., ocean zoning), we need improved interdisciplinary research strategies for, and understanding of, how biophysical processes operate at the small scales contained within MPAs. The Hopkins Marine Life Refuge (now part of the Lovers Point State Marine Reserve) and the associated Hopkins Marine Station provide a unique opportunity to develop interdisciplinary research, education and monitoring programs that will contribute to increasing our understanding of the marine ecosystems of Monterey Bay in the face of increasing pressure from climate change and current and future local impacts. With the support of the Hopkins Marine Station’s Marine Life Observatory, we are establishing the Kelp Forest Project, which will function to support a diverse array of (suite of advancing) research projects directed toward furthering (increasing) our understanding of the nearshore kelp forest ecosystem.
The Physical-Biological Coupling Kelp Forests Project
One of the initial research projects taken up by the Kelp Forest will explore the connections of small-scale physical and biological processes that affect nearshore fish assemblages, using a combination of physical, chemical and biological observations. In addition to (in conjuction with) investigating the physical-biological coupling in kelp forest ecosystems, researchers will seek to develop novel cost-effective sampling and automated monitoring methods necessary for measuring juvenile fish recruitment to their associated communities.
Adult fish aggregate and disperse depending on physical conditions and the distribution of their prey, predators, and competitors. Recruitment pulses are typically infrequent and unpredictable and may be missed if sampled with a fixed schedule. Moreover, surveys that do not account for how environmental conditions influence the abundance and distribution of larval, juvenile, and adult fish are likely highly inefficient and inaccurate. Results from studies of the transport of marine organisms and their larvae, at scales ranging 10-100 km suggest connectivity arises from large-scale current and eddy patterns driven by upwelling pulses.
To bridge these gaps, long-term empirical datasets are needed to support the development
of a mechanistic understanding of how ocean flows at the scale of a marine reserve (e.g.,
100-1000s m) interact with ecological processes. This knowledge is essential to link
biophysical processes, spatial management efforts, and the interactions between natural
and human systems and has wide-reaching implications for the success of ongoing and
future ecosystem-based management efforts.
The Physical-Biological Coupling Kelp Forests Project will explore the development of effective sampling designs and technologies for monitoring ecosystem function and physical-biological coupling in kelp forests. The objectives of this project include the following:
1. Quantify the effect of the nearshore hydrodynamics on juvenile and adult rocky reef fish behavior and abundance and identify relatively easy-to-measure processes (e.g. ocean swell) as proxies that adequately characterize their distribution.
2. Investigate the effect of the nearshore hydrodynamics on fish and invertebrate recruitment.
3. Utilize our results to optimize the design of sampling surveys of larval, juvenile, and adult fish assemblages in nearshore habitats by incorporating effects of local hydrodynamic regimes.
Environmental coastal engineering
Goal: To develop a kelp forest Project to identify key physical processes affecting fish populations
Goal: To quantify the effect of nearshore hydrodynamics and environmental conditions on rocky-reef fish behavior, abundance, recruitment and juvenile survivorship and to identify the mechanisms that link physical, environmental and biological processes.
Benefits and Applications
Links between local hydrodynamic conditions, including small-scale flow and swell conditions, recruitment and the structure of fish assemblages have important implications for not only the accurate monitoring of fish populations and communities but for marine reserve design and assessment. The research findings of the Physical-Biological Coupling Kelp Forests Project will further our understanding of how hydrodynamic conditions affect juvenile and adult fish assemblages and influence larval recruitment in the highly variable environment of nearshore rocky reefs at the local scale. In addition, results will generate new understanding on how local flow conditions bias recruitment sampling and dive survey counts, which at the present time operate as fixed designs independent of local hydrodynamic conditions. A better understanding of hydrodynamic conditions and biological responses will inform adaptive sampling designs appropriate for monitoring marine reserves in Monterey Bay and other upwelling regions, and develop automated monitoring of physical and biological processes in kelp forest ecosystems. The adaptive sampling designs that are developed will further facilitate the efficient collection of accurate data necessary for evaluating the function and management of marine reserves through cost-efficient methods of surveying fish assemblages.