Freshwater mussel records collected by the Maryland Department of ...

More documents

Recommendations

Info

of A. heterodon. The apparent rarity of tessellated darter from a few sites where A. heterodon was collected poses several management implications. Locally, the populations may not be reproducing due to a lack of a suitable host or because host abundance is too low to support consistent recruitment (Haag and Warren 1998). Conversely, the absence of tessellated darter from a site does not entirely discount their presence at nearby locations given their high site fidelity (McLain and Ross 2005). Finally, other regionally suitable, yet to be documented hosts may exist. Glochidial release rates of A. heterodon are highest during April and May (Michaelson and Neves 1995, McLain and Ross 2005); therefore, a comprehensive list of regional hosts would require sampling when anadromous fishes ascend streams to spawn. A diverse assemblage of host fishes exists for E. complanata in Maryland (Young 1911, Matteson 1955, Watters et al. 2005, Kneeland and Rhymer 2008); however, recent studies indicate American eels are superior hosts for E. complanata (Lellis, unpublished data). The diversity of host species likely allows them to inhabit a broad range of habitats, though it is increasingly apparent that the absence of eels eventually results in the absence of E. complanata or depressed populations (Devers 2009). It is unknown if a density-dependent relationship exists between American eels and E. complanata that would further explain patterns in their distribution (Haag and Warren 1998), but this is likely given the high rate of glochidial transformation on eels and reproductive success of E. complanata at varying densities (Downing et al. 1993, Lellis, unpublished data). Two glochidial hosts (bluegill and largemouth bass) of E. fisheriana (O’Dee and Watters 2000) were extant throughout much of its range in Maryland, suggesting their absence from streams may not entirely be related to the lack of a suitable host. These fishes are not native to Maryland and often found in low abundance, indicating an unknown host must have existed prior to their introduction. Three fishes native to Maryland that O’Dee and Watters (2000) found not to transform glochidia were collected at sites with E. fisheriana and may warrant further investigation. The common practice of stocking nonnative centrachids into private and public waters has likely played a role in the ubiquitous distribution of host generalists like P. cataracta and the presence of mussels in reservoirs (Long 1983). Investigating fish frequently collected with mussels or hosts of congeneric mussels for glochidial infestations may answer whether mussel distribution in Maryland is affected by host availability. For example, American eel was found at a majority of sites where mussels were present; however, they have been confirmed as a glochidial host for only a single mussel species in Maryland. Hosts of other Alasmidonta spp., including fallfish, largemouth bass, and pumpkinseed, were sporadically collected at sites with A. heterodon. Furthermore, nine species identified as hosts for P. grandis (Trdan and Hoeh 1982, Watters et al. 2005, Cummings and Watters 2009) were present at sites with P. cataracta. The host fish of lanceolate Elliptios are poorly understood and the taxonomic uncertainty of these species makes the process even more troublesome. Examining congeneric fish for glochidia may be another possible strategy to identify glochidial hosts. The congeneric to the widespread tessellated darter, Etheostoma nigrum (johnny darter) has been documented as a host for E. fisheriana and the conger to P. cataracta, yet johnny darter is not sympatric with either species in Maryland. Conversely, the closely related tessellated darter was collected at most sites (≥80%) with these mussels. Sculpin (Cottus spp.) serve as hosts for a suite of mussels, yet only for a few species in 50
Maryland (Cummings and Watters 2009). Examining live fish in the field or preserved fish for glochidia may provide more conclusive answers regarding natural host use and the recruitment of mussels in Maryland. Laboratory studies of host use and suitability should also be considered because of the critical information it could provide to freshwater mussel management mussels and the streams in which they reside. The exotic Asian clam, C. fluminea, has spread throughout most of Maryland after its introduction several decades ago (Counts 1986). Their effects upon native mollusks are poorly understood and undocumented (Strayer 1999a), yet they are often identified as a cause for declines in unionid populations (Clarke 1986, 1988). Cohen et al. (1984) found that locally dense populations of C. fluminea removed a majority of the phytoplankton within a reach of the Potomac River, which suggests their ability to out compete unionids for food. In at least one study (Ricciardi et al. 1998), C. fluminea coexisted with dense and diverse unionid assemblages in the Mississippi River basin and did not appear to significantly affect the abundance or distribution of unionids. Differing aspects of their life history, diet, and habitat may facilitate this overlap (Strayer 1999a). At this time, there appears to be no wide-ranging effects that can be attributed to C. fluminea. They are frequently found in streams with high mussel abundance, diverse assemblages, or rare species, such as Brown’s Branch, Tuckahoe Creek, and Sideling Hill Creek, as well as streams that are heavily impaired by poor water quality and land alteration. The spatial coverage of the MBSS will continue to describe the distribution of C. fluminea and potentially document finer scale interactions with native unionids. Several freshwater mussel species continue to remain under-represented in this report because the MBSS design focuses on 1 st -4 th order, wadeable streams. Significant mussel resources have been documented in Maryland streams ≥4 th order, yet the environmental conditions found coincident with these mussel assemblages have received little attention. The number of sites where mussels could potentially be encountered during MBSS sampling is initially limited because a majority of streams sampled in a given year are 1 st order. Recording unionid presence and not species level identification during MBSS Round 2 (2000-2004) and a vast majority of sites sampled from 2005-2006 further limited the number of freshwater mussel observations by approximately 100 sites. Preliminary examination of these records found that many exist near locations where NHP previously documented imperiled mussels. While an earlier version of this report suggested that NHP mussel records could be combined with MBSS data to increase sample sizes for rare species, this was not undertaken because of the vast differences between the sampling methods, apparent detection rates of the two programs, and the further reliance on presence-absence data. While a handful of sites sampled by NHP exist in close proximity to MBSS sites where mussels were not encountered, the majority exist well away from a referable MBSS site. Since mussel data has already been collected at these sites, MBSS surveys should be conducted to permit these data to potentially be included with results from MBSS Round 3 (2005-2009). We will cautiously examine how merging NHP mussel records with MBSS data affects our prior analyses as we collect targeted data over the coming years. Targeted sampling would also be required to increase the detection of A. implicata, L. r. radiata, L. ochracea, L. nasuta, and U. imbecillis, species primarily found in large rivers, lentic systems, or tidally-influenced waters (Bogan and Proch 1997). Currently, most records for these and 51
Page 1 and 2:
Freshwater mussel records collected
Page 3:
Freshwater mussel records collected
Page 6 and 7:
List of Figures Figure Number Page
Page 8 and 9: List of Tables Table Number Page 1.
Page 11 and 12: INTRODUCTION The diversity of fresh
Page 13 and 14: species richness, host abundance, a
Page 15 and 16: Table 1. Number of sites sampled by
Page 17 and 18: Table 2. Frequency of occurrence fo
Page 19 and 20: Figure 3. continued A P A P A P p =
Page 21 and 22: Figure 3. continued A P A P A P 0 5
Page 23 and 24: Since 2007, A. undulata Say 1817 ha
Page 25 and 26: Anodonta implicata Say 1829 was enc
Page 27 and 28: Table 3. Frequency of occurrence fo
Page 29 and 30: Figure 8. continued A P A P A P p =
Page 31 and 32: Figure 8. continued A P A P A P 0 5
Page 33 and 34: In 2009, E. fisheriana was collecte
Page 35 and 36: Figure 10. Box-and-whisker plots of
Page 37 and 38: Figure 10. continued. A P A P A P 0
Page 39 and 40: Figure 10. continued A P A P A P 0
Page 41 and 42: Elliptio producta Conrad 1836 has p
Page 43 and 44: Lampsilis radiata radiata Gmelin 17
Page 45 and 46: Leptodea ochracea Say 1817 has been
Page 47 and 48: Pyganodon cataracta had previously
Page 49 and 50: Figure 19. Box-and-whisker plots of
Page 55 and 56: Corbicula fluminea is a non-native
Page 57: (Black 2001, Wang 2007b). A lack of
Page 61 and 62: REFERENCES Allan, J.D., & A.S. Flec
Page 63 and 64: Kelly, M.W., & J.M. Rhymer. 2005. P
Page 65 and 66: ——. 1999a. Effects of alien spe
Page 67 and 68: Young, D. 1911. The implantation of
Page 70 and 71: 8-digit watershed Number 8-digit wa
show all

Freshwater mussel records collected by the Maryland Department of ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?