1 Introduction: Cape Falcon Marine Reserve Lander Video Fish Report

Data are not presented for Lander Fish analysis at Cape Falcon Marine Reserves at this time. The purpose of this brief report is to document the survey effort completed by video lander at Cascade Head and to discuss future monitoring efforts.

1.1 Sample Sizes

1.1.1 Video Lander Sample Sizes

Fig. 1: Sample sizes obtained by video lander at Cape Falcon Marine Reserve at its two associated comparison areas

Fig. 1: Sample sizes obtained by video lander at Cape Falcon Marine Reserve at its two associated comparison areas

1.1.2 Video Lander Sample Sizes

Fig. 1: Sample sizes obtained by video lander at Cape Falcon Marine Reserve at its two associated comparison areas

Fig. 1: Sample sizes obtained by video lander at Cape Falcon Marine Reserve at its two associated comparison areas

2 Discussion

Due to staff and budget limitations, the marine reserves team was unable to analyze and include video lander data from Cape Falcon in the 2022 Synthesis. Current analytical efforts focused on reporting video lander results from the two oldest marine reserves: Redfish Rocks Marine Reserve and Otter Rock Marine Reserve. Only two years of data have been collected with the video lander at Cape Falcon and its comparison areas. Weather windows to access the Cape Falcon Marine Reserve and its comparison areas were limited with the small vessels contracted for monitoring surveys. These have resulted limited usable lander drops, and additional survey effort will be needed for a statistical analysis of these data.

The biggest challenge with the lander monitoring tool is the high effort required to generate useable data (drops) for analysis. There are many reasons why lander drops may be excluded throughout the process from data collection to video review and/or exclusion for methodological changes as the tool develops through time. The result has led to unequal sample sizes through the years, despite days of fieldwork that would suggest otherwise. This combined with the long staff time required to perform video review and quality assurance / control on the data (Watson & Huntington 2021) makes this an inefficient monitoring tool as it is currently used.The first ODFW monitoring report questioned the use of the lander for detecting change between sites because of low abundances and limited species-specific identification, and that challenge remains after additional years of tool development and sampling effort.

The lander tool was developed to provide additional data on the invertebrate and biogenic habitat communities; however we found the data unsuitable for inclusion in this report. Initial exploration into the invertebrate data, resulted in high percentages of lander drops with either unidentified invertebrate species or with no invertebrate species recorded. For example with our focal invertebrate species, the percent of lander drops with zeros ranged from 80 - 99%, even when we pooled data across sites. This is likely a result of lander development, where its construction focused on camera angles and view frames appropriate for assessing fish, and invertebrates typically require different camera position and video review requirements. With our biogenic habitat data, we found that two most commonly observed categories were also the categories with the largest error amongst reviewers documented in the early development of this tool (Lawrence et al 2015). A simulation revealed that the current distribution of cover in these categories was within the range of random guessing, and with staff turnover through the years we had low confidence in the reliability of data. With other monitoring tools more efficient to detect changes between sites or trends by year, the future use of monitoring with this tool is unlikely.

3 References

Lawrence K.A., Watson J.L., Huntington B.E. (2016). A method for quantifying bioegnic habitat from stationary underwater video. ODFW Informational Report No. 2016-04. Marine Resources Program. Oregon Department of Fish and Wildlife. Newport, OR.

Watson, J.L, and B.E. Huntington. 2021. Comparing angling, underwater visual census, and video methods to refine [fishery independent] long-term monitoring of a reef fish assemblage in a temperate marine reserve. Science Bulletin 2021-15. Oregon Department of Fish and Wildlife, Newport.