The Vantuna Research Group encourages its undergraduate research assistants to participate in the honors program and the Occidental College Summer Research Program. The students below have completed a proposal, secured funding for supplies, room & board and a stipend, and will be conducting independent research projects over the summer.
Sabrina Moffly (Summer 2014)
Age Distribution and Growth Rates of Garibaldi from Santa Catalina Island
The Garibaldi (Hypsypops rubicundus) is one of the most well-known fish inhabiting the rocky reef habitats on the California coast due to its bright orange hue. However, there has been little scientific research conducted on this fish because it has been protected by law as the California state marine fish since 1995. These regulations were put into place to prevent overfishing of the popular orange fish by the commercial aquarium business. The Vantuna Research Group (VRG) has been allowed the opportunity to collect 160 individuals of this species in order to work on completing a life history study. Having individuals from the island and mainland fish populations in southern California will allow for a wide variety of data to be collected that will aid with critical management options concerning this species. For my project, I will be determining age distribution and growth rates for Garibaldi at Santa Catalina Island, California. In order to accurately determine the age of the 55 Garibaldi previously collected from Santa Catalina Island, I will dissect them and remove their inner ear bones, known as otoliths, which have daily and annual rings similar to tree rings then I will cut and read the otoliths to determine each fish’s age in the Moore Laboratory of Zoology. I will then compile the data and determine their age distribution and growth rates. The goal of this project would be to produce an age and growth curve which will add to the greater understanding of the life history of the Garibaldi.
Hypsypops rubicundus, the garibaldi, is a Pomacentrid fish found in the waters of southern California. Adult Garibaldi are bright orange while juveniles are predominantly orange with bright blue spots. These fish inhabit rocky bottom habitats, preferring to live in and around small crevices or caves (Limbaugh, 1964). Male Garibaldi are nesters and have a highly defined territories, which they fiercely protect while females, juveniles and “bachelor” males move more freely between territories. In general, most Garibaldi stay in a rather limited area (Clarke, 1970; Limbaugh, 1964). Garibaldi eggs are kept in the nest under the protection of the male until they hatch, marking the end of parental care (Limbaugh, 1964). The territorial behavior exhibited by the fish seems to be related to reproduction rather than any other biological or ecological factors (Clarke, 1970). Larvae leave the planktonic stage to settle in the rocky reef habitat from July to November and they are often found in the same location many months later having created a permanent residence usually near other adult Garibaldi. Mortality rates among these fish are seemingly very low once they settle; therefore it is important to know their age and growth rates to get a better understanding of the population dynamics. Also it is important to see if recruitment of juveniles to habitats is balanced with natural mortality, which is needed to keep an average and stable density of fish in one area (Clarke, 1970).
Historically, the Garibaldi has been a highly protected species out of fear that there would be overfishing for marine aquariums since they are easily caught (Limbaugh, 1964). Because of increased legislation protecting the fish (Morrow, 1994), there has been a decrease in scientific research and collection of the garibaldi resulting in an overall lack of knowledge on its life history. However, the Vantuna Research Group (VRG) has been given the opportunity to further study the life history of the garibaldi by collecting fish from certain locations on the mainland and at Santa Catalina Island. Age and growth, two important life history traits, have been recorded previously yet only on a small scale using outdated and moderately inaccurate aging techniques that rely on looking at the fish’s scales. Knowing the life history of a fish, even just one aspect like its growth or age, can be important in understanding the population dynamics, what type of environments they inhabit, and fishery management (King and McFarlane, 2003). The Garibaldi’s life history is specifically important because they are an integral part of the rocky reef ecosystem in southern California. Age and growth are important factors to look at because it will help in the understanding of localized production on these rocky reefs, since Garibaldi do not often leave their territory. Also Santa Catalina Island is the site of recently created marine protected areas and life history information will be important in evaluating how well these sanctuaries work. This summer, I will be determining the age distribution and growth curve of the Garibaldi population at Santa Catalina Island. Once this project is completed, we will have substantially more information on the age and growth of California's most famous marine fish.
I will determine the ages of 55 Garibaldi collected from Catalina by looking at their otoliths. The Garibaldi that I will use have previously been collected from Catalina Island by Scott Hamilton of the Marine Science Institute at the University of California, Santa Barbara. They collected 55 fish, ranging from juvenile to adult, by pole spear from Isthmus Reef and Lion’s Head Reef from August 20- 24th, 2013 (Figure 2). The VRG has already submitted the necessary and proper paperwork (IACUC) to perform the tasks described in this project. When the fish were received, their weight was recorded to the nearest gram prior to freezing. Total length and standard length to the nearest hundredth of a millimeter were also recorded. Then the gut, gonads, and sagittal otoliths were removed and preserved or retained for further study. Once the otoliths were extracted they were cleaned and stored.
Previously, age and growth studies for the Garibaldi have predominantly been done by looking at the rings laid down on the fish’s scales, which are easily collected without harming the fish. However, this does not always give an accurate estimate of the age because fish are constantly shedding scales making the rings unreliable. Therefore, I will count the rings on the inner ear bone of the fish, or otolith, to more accurately determine age, which will create a more accurate growth curve. Annual growth rings in adults and daily growth rings in juveniles can be seen in the otolith thus allowing for the rings to be counted to determine an accurate age of the fish.
The otoliths need to be sectioned in order to properly read the rings and age the fish. With the larger adult otoliths this will be accomplished by gluing them to small wood blocks and cutting a transverse section of approximately 0.5mm thick using a Buehler-Isomet low-speed saw with a 0.75-mm acetate spacer (Allen et al. 1995). This section will then be polished and prepared to on a slide for photography under a dissecting microscope. Then I will take a digital picture that will be used to count the annual rings (Williams et al. 2007). The age is then approximated by counting the annuli or the complete pairs of opaque and translucent rings found on each otolith. The number of annuli will be recounted for each otolith by two or three independent reader until concordance is found and the age is finalized (Williams et al. 2012). The juvenile otoliths are too small for the adult process so they will instead be submerged in immersion oil then photographed and the counting process will be the same as for adults (Findlay and Allen 2002). Once the individual ages have been determined a growth curve will be calculated using the von Bertalanffy growth function, the Gompertz growth function, and the power function (following protocols in Williams et Al. 2012). Additionally, I will determine if there is a difference in growth rates between males and females. Males are often recorded as older and therefore larger but this was based off of scale aging, which is not always precise (Limbaugh, 1964). I will use these three different functions to create a growth curve for the males, females and combined sexes.
Allen, L., Hovey, T., Love, M., and Smith, J. 1995. The life history of the spotted sand bass (Paralabrax maculatofasciatus) within the Southern California Bight. California Cooperative Oceanic Fisheries Investigations Reports. 36: 193-203.
Clarke, T. A. 1970. Territorial behavior and population dynamics of a pomacentrid fish, the garibaldi, Hypsypops rubicunda. Ecological Monographs. 40: 189-212.
Findlay, A., and Allen, L., 2002. Temporal patterns of settlement in the temperate reef fish Paralabrax clathratus. Marine Ecology Progress Series. 238:237-248
King, J. R. & McFarlane, G. A. 2003. Marine Fish life history strategies: applications to fishery management. Fisheries Management and Ecology. 10: 249-264
Limbaugh, C. 1964. Notes on the life history of two California pomacentrids: garibaldis, Hypsypops rubicunda (Girard), and blacksmiths, Chromis punctipinnis (Cooper). Pacific Science. 18: 41-50.
Morrow, B. 1995. California Assembly Bill 77.
Williams, J., Allen, L., Steele, M., and Pondella, D. 2007. El Nino periods increase growth of juvenile white seabass (Atractoscion nobilis) in the Southern California Bight. Marine Biology. 152:193-200.
Williams, J. P., Claisse, J. T., Pondella, D. J., Medeiros, L., Valle, C. F., and Shane, M. A. 2012. Patterns of life history and habitat use of an important recreational fishery species, spotfin croaker, and their potential fishery implications. Marine and Coastal Fisheries: Dynamics, Management, and Ecosystem Science. 4:71-84.
Adrienne Mikovari (Summer 2013)
Abundance, Distribution, and Size Frequency of Three Emergent Fishery Species in Palos Verdes, California
Introduction, Objectives, and Procedures
The rocky reefs and kelp forests of southern California provide a sheltered home to an array of specialized plants and animals (Ricketts et al. 1985). Encompassing 46% of southern California’s coastline, rocky reefs support an extensive ecosystem of algae, invertebrates, fish, birds and mammals that make this region a critical habitat for recreational and commercial fisheries (Pondella et al. 2011). Within this rich and dynamic environment, three emergent marine invertebrate fisheries, Kellet’s Whelk (Kelletia kelletii), Wavy Turban Snail (Megastraea Undosa), and Giant Keyhole Limpet (Megathura crenulata), have grown substantial commercial importance in the last 20 years.
California Fish and Wildlife in 2001 and 2008 reported Kellet’s Whelk and Wavy Turban Snail fishery catches have been drastically increasingly since the early 1990s (CA Fish and Game 2004; CA Fish and Game 2010). Wavy Turban Snail landing began to peak in 1998 at 70,000 pounds while Kellet’s Whelk landings data increased 81% from 2005 to 2006 at 191,177 pounds (Figure 1 and Figure 2). Both species are becoming a popular food source and an overseas market in response to closure and decline of other macroinvertebrate fisheries. For the past forty years, the Giant Keyhole Limpet has been commercially important because of the promising biomedical potential of the respiratory pigment, keyhole limpet hemocyanin (KLH; Curtis et al. 1970). Today, KLH is widely used in experimental immunology and is clinically used as an immunotherapeutic agent and general vaccine component. Although there is no status report on the fishery, Giant Keyhole Limpets remain a popular catch for their KLH and it is unknown whether current natural limpet stocks can satisfy a growing commercial demand .(Harris and Markl 1999).
Despite increasing commercial importance in southern California, there is scant life history data and ecological studies in southern California on these invertebrates making it difficult to implement viable management policies. New recreational and commercial regulations were placed on the Kellet’s Whelk fishery in March of 2012, but there remain virtually no regulations on the Wavy Turban Snail and Giant Keyhole Limpet. Therefore, in response to increasing demand, it is important to collect life history baseline data that will inform fisheries management on species demographic parameters. Some concerns are the changes in the abundance of these key species that may disrupt the balance of trophic relationships and possibly lead to trophic cascades within the rocky reef ecosystem (Denny and Gaines 2007). One study near the California Channel Islands (Halpern et al. 2006) identifies Kellet’s Whelk as a key predator species that impacts urchins, limpets, and snails—key grazers of kelp and algae. Rapid removal may also lead to complete closure of a fishery as was seen with the abalone fishery in 1996 where lack of knowledge about abalone’s life history resulted in overfishing and a population crash that still hasn’t recovered today (CA Fish and Wildlife 2001). Without the necessary ecological information, we cannot create sustainable management practices nor predict the environmental impacts of the invertebrate fisheries as they become more prominent in the future. Therefore, monitoring these invertebrate populations and assessing their biological roles is essential in maintaining viable fishery regulations. To help aid in this process, the research questions I will be investigation this summer is: What abiotic and biotic conditions influence the population distributions of Kellet’s Whelk, Wavy Turban Snail, and Giant Keyhole Limpet along the Palos Verdes Peninsula?
In 2004 and 2007 to 2012, the Vantuna Research Group at Occidental College collected baseline size frequency data of invertebrate populations along the rocky reefs of Southern California. The Palos Verdes Peninsula is a prominent rocky reef area in the Santa Monica Bay region where there is substantial rocky reef habitat and kelp canopy cover that supports hundreds of such invertebrates (Claisse et. al. 2012). I intend to join the VRG this summer in the measuring, weighing, and sizing of the three key invertebrates, Kellet’s Whelk, Wavy Turban Snail, and Giant Keyhole Limpet, to better understand their population densities and distributions in Santa Monica Bay. Data will be collected by SCUBA and modified standard CRANE methodology at 11 reefs along the Palos Verdes Peninsula (Figure 3). The goal of this project is to begin documenting the ecological role of these invertebrates by comparing species abundance and size frequencies to various reef characteristics. This study will begin compiling important life history information that combined with previous data will help management fisheries implement effective regulations and ultimately avoid major fishery collapses in the future. I hypothesize that keyhole limpet and wavy turban snail abundance will positively correlate with benthic algae and Kellet’s Whelk abundance will correlate with herbivorous invertebrate abundance.
Figure 1: Commercial Landings of Kellet’s Whelk (Kelletia kelletii) from 1979-2008. Source: CA Fish and Game 2004.
Figure 2: Commercial Landings of Wavy Turban Snail (Megastraea Undosa) from 1916-1999. Source: CA Fish and Game 2001.
Figure 3: Palos Verdes Peninsula Dive Sites. Source: Claisse et. al 2012
California Department of Fish and Game. 2004. Annual Status of the Fisheries Report. 8-1 to 8-15.
California Department of Fish and Game. 2010. Status of the fisheries report an update through 2008: Kellet’s Whelk.
Claisse, J. T., D. J. Pondella, II, J. P. Williams and J. Sadd. 2012. Using GIS Mapping of the Extent of Nearshore Rocky Reefs to Estimate the Abundance and Reproductive Output of Important Fishery Species. PLoS ONE 7(1):e30290.
Curtis, J.E., Hersh, E.M., Harris, J.E., McBride, C., Freireich, E.J., 1970. The human primary immune response to keyhole limpet hemocyanin: interrelationships of delayed hypersensitivity, antibody response and in vitro blast transformation. Clin. Exp. Immunol. 6, 473–491.
Denny, Mark W., and Steven D. Gaines. 2007. Encyclopedia of tidepools and rocky shores. Berkeley: University of California Press.
Halpern et al. 2006. Strong Top-Down Control in Southern California Kelp Forest Ecosystems. Science 312: 1230-1232.
Harris JR, Markl J. 1999. Keyhole limpet hemocyanin (KLH): A biomedical review. Micron 30597-623.
Leet S. William, Christopher Dewees M., Richard Klingbeil, and Eric Larson J. 2001. California’s Living Marine Resources: A Status Report. The California Department of Fish and Game.
Ricketts, Edward Flanders, Jack Calvin, Joel W. Hedgpeth, and David W. Phillips. 1985. Between Pacific tides. Stanford, Calif: Stanford University Press.
Pondella, D., J. Williams, J. Claisse, R. Schaffner, K. Ritter and K. Schiff. 2011. Southern California Bight 2008 Regional Monitoring Program: Volume V. Rocky Reef. Southern California Coastal Water Research Project, Costa Mesa, CA. 116 p.
Binh Vuong (Summer 2013)
Surfgrass (Phyllospadix spp.) is a type of seagrass predominantly found in the water of rocky shores that are exposed to high-energy waves. This unique habitat has created challenges for thorough research on this species in its natural environment. Palos Verdes is one area along the Pacific coast of North America that sustains many local surfgrass communities in such unique habitat. This area consists of affluent residential communities that sit atop the Palos Verdes Peninsula, with the rocky shores ecosystems below. However, the surfgrass populations there are declining due to urchin barrens and anthropogenic activities from the Palos Verdes suburb. A storm drain that opens right into the water can be seen on the shore nearby, and it is a possible direct pollution source onto surfgrass in the vicinity. Unfortunately, to date there has been no research on physiological damage from the pollution to this seagrass. Therefore, my research question is: "How does the storm drain runoff from Palos Verdes affect the water and the existing local surfgrass population at the site, and will this runoff impede ongoing surfgrass restoration projects?" To address this question, I plan to conduct simultaneous laboratory experiments and field-work observations.
- Inspect the sewage pollution level in the water of Phyllospadix at Honeymoon Cove.
- Determine how this pollution affects the growth development of the local surfgrass.
- Inspect the rate and strength of culturing surfgrass in laboratory tanks in 10 weeks.
- Address the status and possible restoration projects of surfgrass at Honeymoon Cove.
Honeymoon Cove, Palos Verdes is a 45-minute drive from Occidental College. This will be the sole survey location for the whole duration of the experiment. Observations of the surfgrass communities, and water sampling of the site will be made weekly. Since Phyllospadix remains submerged under water even at mean low low tide, scuba diving will be needed in order to collect female specimens and put them in ziplock bags.
I plan to collect wild surfgrass seedlings to grow in laboratory tanks, and to plant in the natural environment at Palos Verdes. Survey sites will occur in shallow subtidal zones with less than 4-meter depth, due to a higher survival rate found here than in intertidal zones (Bull et al. 2004). In laboratory, seeds will be collected by passing a finger along the spadix of the female plants, then germinated in petri dishes. To culture plants, I hope to replicate a smaller indoor model that resembles the 2010 transplant concrete system of Park & Lee. Simultaneously, I will be planting plants in areas near the original surfgrass beds for growth comparison with the ones being cultured.
Observations of the growth of the cultured surfgrass will be compared to that of the wild surfgrass. Any growth difference between the two types will be analyzed to determine whether pollution is the catalyst. Survivorship and growth will be closely monitored. Length measurements will make up the core data.
Figure 1. A survey site at mean low low tide. Phyllospadix are underneath the water.
Water sampling of Palos Verdes, especially at Honeymoon Cove, will be conducted to examine the level of pollution. Testing of the sampled water with various chemicals will be used to identify the main compound components. I will further research these compounds for any properties that could damage the physiology of surfgrass.
Figure 2. The Palos Verdes suburb and the storm drain runoff (circled in red).
Balestri, E., F. Vallerini, C. Lardicci. Storm-generated fragments of the seagrass Posidonia oceanica from beach wrack- A potential source of transplants for restoration. Biological Conservation, 144: 1644-1654.
Bull et al. 2004. An Experimental Evaluation of Different Methods of Restoring Phyllospadix torreyi (Surfgrass). Restoration Ecology, 12(1):70-79.
DeMartini, E. E. 1981. The Spring-Summer Ichthyofauna of surfgrass (Phyllospadix) Meadows Near San Diego, California. Bulletin Southern California Academy of Sciences, 80(2):81-90.
Gibbs, R. E. 1902. Phyllospadix as a Beach-builder. The American Naturalist, 36(422):101-109.
Park, J. and K. Lee. Development of transplantation method for the restoration of surfgrass, Phyllospadix japonicus, in an exposed rocky shore using an artificial underwater structure. Ecological Engineering, 36:450-456.
Reed et al. 1998. Studies on germination and root development in the surfgrass Phyllospadix torreyi: implications for habitat restoration. Aquatic Botany, 62: 71-80.
Morgan Winston (Summer 2012)
A description of Morgan's summer research project:
With approximately 12,000 acres of marine habitat, the San Diego Bay is the largest naturally occurring marine embayment between San Francisco and Scammon’s Lagoon (central Baja CA) and is home to a wide diversity of species (Allen et al. 2002). This important ecosystem is highly productive, with an abundance of juvenile fish that grow up in the extensive nursery habitat of eelgrass. Nearby ecosystems are supported by production in the San Diego Bay, as the fish migrate out into the open ocean once they have reached adulthood. The fish species not only support ecologically important and endangered avian species, but also recreational and commercial fisheries.
In 2005 and 2008, the Vantuna Research Group at Occidental College conducted a survey of the fish populations in the San Diego Bay, continuing work that had been completed from 1994 to 1999. From 1994-1999, surveys were taken quarterly and in 2005 and 2008, they were done in both April and July of each year. This study is scheduled to again take place in April and July of 2012. The goal of this ongoing research is to identify and calculate the use of the fishery populations in the bay, recognize the habitats and their nursery function that are support juvenile fish species, and ascertain which areas of the bay are supporting populations of fish that are classified as forage species for endangered avian species in the environment (Pondella and Williams 2009). The studies have been researching nursery area function, fish species and composition, ecological importance of the species, fish assemblage structure, water quality parameters, and fish density and biomass estimates, among other physical and chemical factors.
I contend that the function of the nursery area is one of the most important aspects of the study, as the health of the environment in which juvenile fish grow up in is integral to the health of the ecosystem as a whole. The entire bay thrives because of the high population of these species and the eelgrass in which the fish live driving the process. In past research, it was found that measurements at eelgrass sites yielded nearly twice as many individual fish and fish species than samples taken at non-vegetated sites (Hoffman et al. 1986). However, though the bay supports a wide variety of marine life, it is heavily polluted by runoff from Chollas Creek, one of the most polluted waterbodies in San Diego County (San Diego Coastkeeper, 2010), and from the shipyards and Navy facilities that reside in the bay. The presence of copper at unhealthy levels has been detected in the bay, with concentrations in the sediment high enough to have adverse effects on benthic fauna (Biggs et al. 2011). Eelgrass populations are declining worldwide, and scientists suspect that in addition to pollution, other causes such as development, commercial fishing, and changes in climate are contributing to this change. Eelgrass is used for shelter for fish larvae settling in estuaries and by juvenile fish before it is time for some of them to migrate from the freshwater bay into the ocean (Jenkins and Wheatley 1997). As a nursery habitat and a vital primary producer, eelgrass is extremely important and the loss of it will have far reaching consequences.
I plan to study the presence of eelgrass in the San Diego Bay, which will help aid in determining the health of the bay’s ecosystem. Estuary dependant fish species, such as the slough anchovy (Anchoa delicatissimma), heavily rely on the bay as a nursery habitat. In the 2008 survey, the slough anchovy was found to be the most abundant species, comprising 35.5% of the catch (Table 1), and the species of highest ecological importance based upon the variables %Number, %Weight, and %Frequency (Pondella and Williams 2009). The slough anchovy was also found to be the dominant species in three out of the four Ecoregions (Figure 1). I propose to look for a correlation between the fish density of the slough anchovy and the presence of eelgrass in the upcoming April and July 2012 surveys. Using GIS files of the eelgrass shown in Google Earth, I will be able to georeference the areas in which eelgrass has been growing in the bay. With maps from 2004 (Figure 2), and one recently done this summer, I can determine the loss/growth of the eelgrass. Considering the rising changes in global climate and the increasing toxicity found in the waters, I hypothesize that there will be a measurable difference.
As a member of the Vantuna Research Group, I will accompany the group down to San Diego this April and July. Four main stations are surveyed- north, north-central, south-central, and south (Figure 3).
Figure 2. San Diego Bay 2004 Eelgrass Survey (US Navy SWDIV Naval Facilities Engineering Command, Port of San Diego, 2004)
Figure 3. Sampling locations of the North (1), North-Central (2), South-Central (3) and South (4) Ecoregions in San Diego Bay. (Pondella and Williams 2009)
At each of these sites, I will note if we encountered eelgrass and compare this to satellite images of the region in years past. I will examine the concentration of the slough anchovy, an important forage species that spends its life in the estuary environment. One of the main questions to be answered will be whether or not there a positive correlation between the density of the slough anchovy and the occurrence of eelgrass. Because of the past surveys, I have data on the number of slough anchovies collected in the bay in previous years. I will then be able to compare this information to the samples obtained during the upcoming 2012 survey.
Table 1. Total abundance of fishes collected in San Diego Bay during April and July 2008 by Ecoregion. (Pondella and Williams 2009)
Figure 1. Total catch of the five numerically dominant species by Ecoregion (Pondella and Williams 2009).
When surveying the fish in the bay, the same protocol will be used this year as in years past. At each of the four Ecoregions (Figure 2), five subhabitats will be sampled (intertidal vegetated, intertidal non-vegetated, nearshore vegetated, nearshore non-vegetated, and deep channel). Gear to be used includes a large seine, a small seine, a square enclosure, a beam trawl, a purse seine, and a semi-balloon otter trawl. At each station, the fish are counted and measured. I will note at each site whether or not there is eelgrass growth present and count/measure all slough anchovies found. This can then be compared to numbers found in years past. Though slough anchovies have been sampled in years past, there has been no further investigation into precisely which areas of the bay they are found relative to the presence of eelgrass. The water at each Ecoregion is tested for water temperature, salinity, dissolved oxygen, and pH; I can use this data in comparison to years past in order to detect the changes that have been occurring in the environment. By looking at the presence of eelgrass and the corresponding population of slough anchovies over time, I will examine if manmade and/or natural factors are causing a change in their environment.
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